ios/chrome/browser/fullscreen/ui_bundled/fullscreen_model.h - chromium/src - Git at Google

 // Copyright 2017 The Chromium Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #ifndef IOS_CHROME_BROWSER_FULLSCREEN_UI_BUNDLED_FULLSCREEN_MODEL_H_
 #define IOS_CHROME_BROWSER_FULLSCREEN_UI_BUNDLED_FULLSCREEN_MODEL_H_

 #include <CoreGraphics/CoreGraphics.h>

 #include <cmath>

 #import "base/observer_list.h"
 #import "ios/chrome/browser/broadcaster/ui_bundled/chrome_broadcast_observer_bridge.h"
 #import "ios/chrome/browser/fullscreen/ui_bundled/scoped_fullscreen_disabler.h"
 #import "ios/chrome/browser/shared/public/features/features.h"
 #import "ios/chrome/browser/toolbar/ui_bundled/fullscreen/toolbars_size_observer.h"
 #import "ios/web/common/features.h"

 class FullscreenModelObserver;
 @class ToolbarsSize;

 // Represents the direction the user is scrolling.
 enum class FullscreenModelScrollDirection : int { kUp, kDown, kNone };

 // Model object used to calculate fullscreen state.
 class FullscreenModel : public ChromeBroadcastObserverInterface,
                         ToolbarsSizeObserver {
  public:
   FullscreenModel();

   FullscreenModel(const FullscreenModel&) = delete;
   FullscreenModel& operator=(const FullscreenModel&) = delete;

   ~FullscreenModel() override;

   // Adds and removes FullscreenModelObservers.
   void AddObserver(FullscreenModelObserver* observer);
   void RemoveObserver(FullscreenModelObserver* observer);

   // The progress value calculated by the model.
   CGFloat progress() const { return progress_; }

   // Whether fullscreen is disabled.  When disabled, the toolbar is completely
   // visible.
   bool enabled() const { return disabled_counter_ == 0U; }

   // Whether the base offset has been recorded after state has been invalidated
   // by navigations or toolbar height changes.
   bool has_base_offset() const {
     CHECK(base::FeatureList::IsEnabled(web::features::kSmoothScrollingDefault));
     return !std::isnan(base_offset_);
   }

   // The base offset against which the fullscreen progress is being calculated.
   CGFloat base_offset() const { return base_offset_; }

   // Returns the difference between the max and min toolbar heights.
   CGFloat get_toolbar_height_delta() const {
     CGFloat top_delta =
         GetExpandedTopToolbarHeight() - GetCollapsedTopToolbarHeight();
     if (top_delta < FLT_EPSILON &&
         GetCollapsedBottomToolbarHeight() >= FLT_EPSILON) {
       CGFloat bottom_delta =
           GetExpandedBottomToolbarHeight() - GetCollapsedBottomToolbarHeight();
       return bottom_delta;
     }
     return top_delta;
   }

   // Returns whether the page content is tall enough for the toolbar to be
   // scrolled to an entirely collapsed position.
   bool can_collapse_toolbar() const {
     return content_height_ > scroll_view_height_ + get_toolbar_height_delta();
   }

   // Whether the view is scrolled all the way to the top.
   bool is_scrolled_to_top() const {
     return y_content_offset_ <= -GetExpandedTopToolbarHeight();
   }

   // Whether the view is scrolled all the way to the bottom.
   bool is_scrolled_to_bottom() const {
     if (base::FeatureList::IsEnabled(web::features::kSmoothScrollingDefault)) {
       return y_content_offset_ + scroll_view_height_ >= content_height_;
     } else {
       return y_content_offset_ -
                  (GetCollapsedTopToolbarHeight() +
                   GetCollapsedBottomToolbarHeight() + safe_area_insets_.bottom +
                   safe_area_insets_.top) +
                  (scroll_view_height_ + GetExpandedTopToolbarHeight() +
                   GetExpandedBottomToolbarHeight()) >=
              content_height_;
     }
   }

   // The min, max, and current insets caused by the toolbars.
   UIEdgeInsets min_toolbar_insets() const {
     return GetToolbarInsetsAtProgress(0.0);
   }
   UIEdgeInsets max_toolbar_insets() const {
     return GetToolbarInsetsAtProgress(1.0);
   }
   UIEdgeInsets current_toolbar_insets() const {
     return GetToolbarInsetsAtProgress(progress_);
   }

   // Returns the toolbar insets at `progress`.
   UIEdgeInsets GetToolbarInsetsAtProgress(CGFloat progress) const {
     return UIEdgeInsetsMake(GetCollapsedTopToolbarHeight() +
                                 progress * (GetExpandedTopToolbarHeight() -
                                             GetCollapsedTopToolbarHeight()),
                             0,
                             GetCollapsedBottomToolbarHeight() +
                                 progress * (GetExpandedBottomToolbarHeight() -
                                             GetCollapsedBottomToolbarHeight()),
                             0);
   }

   // Increments and decrements `disabled_counter_` for features that require the
   // toolbar be completely visible.
   void IncrementDisabledCounter();
   void DecrementDisabledCounter();

   // Force enter fullscreen without animation. Setting the progress to 0.0 even
   // when fullscreen is disabled.
   void ForceEnterFullscreen();

   // Recalculates the fullscreen progress for a new navigation.
   void ResetForNavigation();

   // Instructs the model to ignore broadcasted scroll updates for the remainder
   // of the current scroll.  Has no effect if not called while a scroll is
   // occurring.  The model will resume listening for scroll events when
   // `scrolling_` is reset to false.
   void IgnoreRemainderOfCurrentScroll();

   // Called when a scroll end animation finishes.  `progress` is the fullscreen
   // progress corresponding to the final state of the aniamtion.
   void AnimationEndedWithProgress(CGFloat progress);

   // TODO(crbug.com/397683326): Move these values to `ToolbarsSize`.
   // Getter for the minimum top toolbar height to use in calculations.
   CGFloat GetCollapsedTopToolbarHeight() const;

   // Getter for the maximum top toolbar height to use in calculations.
   CGFloat GetExpandedTopToolbarHeight() const;

   // Getter for the maximum bottom toolbar height to use in calculations.
   CGFloat GetExpandedBottomToolbarHeight() const;

   // Getter for the minimum bottom toolbar height to use in calculations.
   CGFloat GetCollapsedBottomToolbarHeight() const;

   // Whenever the height of the top or bottom toolbar changes.
   void ToolbarsHeightDidChange();

   // Setter for the height of the scroll view displaying the main content.
   void SetScrollViewHeight(CGFloat scroll_view_height);
   CGFloat GetScrollViewHeight() const;

   // Setter for the current height of the rendered page.
   void SetContentHeight(CGFloat content_height);
   CGFloat GetContentHeight() const;

   // Setter for the top content inset of the scroll view displaying the main
   // content.
   void SetTopContentInset(CGFloat top_inset);
   CGFloat GetTopContentInset() const;

   // Setter for the current vertical content offset. Setting this will
   // recalculate the progress value.
   void SetYContentOffset(CGFloat y_content_offset);
   CGFloat GetYContentOffset() const;

   // Setter for whether the scroll view is scrolling. If a scroll event ends
   // and the progress value is not 0.0 or 1.0, the model will round to the
   // nearest value.
   void SetScrollViewIsScrolling(bool scrolling);
   bool IsScrollViewScrolling() const;

   // Setter for whether the scroll view is zooming.
   void SetScrollViewIsZooming(bool zooming);
   bool IsScrollViewZooming() const;

   // Setter for whether the scroll view is being dragged.
   void SetScrollViewIsDragging(bool dragging);
   bool IsScrollViewDragging() const;

   // Setter for whether the scroll view is resized for fullscreen events.
   void SetResizesScrollView(bool resizes_scroll_view);
   bool ResizesScrollView() const;

   // Setter for the safe area insets for the current WebState's view.
   void SetWebViewSafeAreaInsets(UIEdgeInsets safe_area_insets);
   UIEdgeInsets GetWebViewSafeAreaInsets() const;

   // Setter for whether force fullscreen mode is active. The mode is used when
   // the bottom toolbar is collapsed above the keyboard.
   void SetForceFullscreenMode(bool force_fullscreen_mode);
   bool IsForceFullscreenMode() const;
   void SetInsetsUpdateEnabled(bool enabled);
   bool IsInsetsUpdateEnabled() const;

   FullscreenModelScrollDirection GetLastScrollDirection() const {
     return fullscreen_scroll_direction_;
   }

   // Sets the last scroll direction. If the direction has changed, the base
   // offset is updated.
   void SetLastScrollDirection(FullscreenModelScrollDirection direction);

   // Updates `speed_` of the fullscreen model accordingly to
   // fullscreen flag `fullscreen transition experiment`.
   void UpdateSpeed();

   // Getter for the speed of fullscren transition.
   CGFloat GetSpeed() { return speed_; }

   // Setter for the toolbar.
   void SetToolbarsSize(ToolbarsSize* toolbars_size);

  private:
   // Returns how a scroll to the current `y_content_offset_` from `from_offset`
   // should be handled.
   enum class ScrollAction : short {
     kIgnore,                       // Ignore the scroll.
     kUpdateBaseOffset,             // Update `base_offset_` only.
     kUpdateProgress,               // Update `progress_` only.
     kUpdateBaseOffsetAndProgress,  // Update `base_offset_` and `progress_`.
   };
   ScrollAction ActionForScrollFromOffset(CGFloat from_offset) const;

   // Updates the base offset given the current y content offset, progress, and
   // toolbar height.
   void UpdateBaseOffset();

   // Updates the progress value given the current y content offset, base offset,
   // and toolbar height.
   void UpdateProgress();

   // Updates the disabled counter depending on the current values of
   // `scroll_view_height_` and `content_height_`.
   void UpdateDisabledCounterForContentHeight();

   // Setter for `progress_`.  Notifies observers of the new value if
   // `notify_observers` is true.
   void SetProgress(CGFloat progress);

   // Returns true if the size of the scroll is more than the threshold to begin
   // entering or exiting fullscreen.
   bool ScrollThresholdExceeded() const;

   // ChromeBroadcastObserverInterface:
   void OnScrollViewSizeBroadcasted(CGSize scroll_view_size) override;
   void OnScrollViewContentSizeBroadcasted(CGSize content_size) override;
   void OnScrollViewContentInsetBroadcasted(UIEdgeInsets content_inset) override;
   void OnContentScrollOffsetBroadcasted(CGFloat offset) override;
   void OnScrollViewIsScrollingBroadcasted(bool scrolling) override;
   void OnScrollViewIsZoomingBroadcasted(bool zooming) override;
   void OnScrollViewIsDraggingBroadcasted(bool dragging) override;
   void OnCollapsedTopToolbarHeightBroadcasted(CGFloat height) override;
   void OnExpandedTopToolbarHeightBroadcasted(CGFloat height) override;
   void OnExpandedBottomToolbarHeightBroadcasted(CGFloat height) override;
   void OnCollapsedBottomToolbarHeightBroadcasted(CGFloat height) override;

   // ToolbarsSizeObserver implementation
   void OnTopToolbarHeightChanged() override;
   void OnBottomToolbarHeightChanged() override;
   // The observers for this model.
   base::ObserverList<FullscreenModelObserver, true> observers_;
   // The percentage of the toolbar that should be visible, where 1.0 denotes a
   // fully visible toolbar and 0.0 denotes a completely hidden one.
   CGFloat progress_ = 0.0;
   // The base offset from which to calculate fullscreen state.  When `locked_`
   // is false, it is reset to the current offset after each scroll event.
   CGFloat base_offset_ = 0.0;
   // Heights of the top and bottom toolbars.
   ToolbarsSize* toolbars_size_;
   // The current vertical content offset of the main content.
   CGFloat y_content_offset_ = 0.0;
   // The height of the scroll view displaying the current page.
   CGFloat scroll_view_height_ = 0.0;
   // The height of the current page's rendered content.
   CGFloat content_height_ = 0.0;
   // The top inset of the scroll view displaying the current page.
   CGFloat top_inset_ = 0.0;
   // How many currently-running features require the toolbar be visible.
   size_t disabled_counter_ = 0;
   // Counts the number of currently-running feature that require to force
   // fullscreen mode.
   size_t force_fullscreen_mode_counter_ = 0;
   // Whether fullscreen is disabled for short content.
   bool disabled_for_short_content_ = false;
   // Whether the main content is being scrolled.
   bool scrolling_ = false;
   // Whether the scroll view is zooming.
   bool zooming_ = false;
   // Whether the main content is being dragged.
   bool dragging_ = false;
   // Whether the in-progress scroll is being ignored.
   bool ignoring_current_scroll_ = false;
   // Whether the scroll view is resized for fullscreen events.
   bool resizes_scroll_view_ = false;
   // The WebState view's safe area insets.
   UIEdgeInsets safe_area_insets_ = UIEdgeInsetsZero;
   // The number of FullscreenModelObserver callbacks currently being executed.
   size_t observer_callback_count_ = 0;
   // Whether updating insets is enabled.
   bool insets_update_enabled_ = true;
   // Whether progress is currently being set.
   bool setting_progress_ = false;
   // Current direction of scrolling initiated by the user.
   FullscreenModelScrollDirection fullscreen_scroll_direction_ =
       FullscreenModelScrollDirection::kNone;
   // Speed of fullscreen transition.
   CGFloat speed_ = 1.0;
   // Time when scrolling started.
   std::optional<base::TimeTicks> start_scrolling_time_ = std::nullopt;
   // True is the scrolling time have been recorded.
   bool is_scrolling_time_recorded_ = false;
   // The minimum scroll amount that will result in beginning to enter or exit
   // fullscreen.
   CGFloat scroll_threshold_ = 0.0;
   // The content offset when the most recent drag event started.
   CGFloat offset_at_start_of_drag_ = 0;

   friend class FullscreenModelTest;
 };

 #endif  // IOS_CHROME_BROWSER_FULLSCREEN_UI_BUNDLED_FULLSCREEN_MODEL_H_
	// Copyright 2017 The Chromium Authors
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#ifndef IOS_CHROME_BROWSER_FULLSCREEN_UI_BUNDLED_FULLSCREEN_MODEL_H_
	#define IOS_CHROME_BROWSER_FULLSCREEN_UI_BUNDLED_FULLSCREEN_MODEL_H_

	#include <CoreGraphics/CoreGraphics.h>

	#include <cmath>

	#import "base/observer_list.h"
	#import "ios/chrome/browser/broadcaster/ui_bundled/chrome_broadcast_observer_bridge.h"
	#import "ios/chrome/browser/fullscreen/ui_bundled/scoped_fullscreen_disabler.h"
	#import "ios/chrome/browser/shared/public/features/features.h"
	#import "ios/chrome/browser/toolbar/ui_bundled/fullscreen/toolbars_size_observer.h"
	#import "ios/web/common/features.h"

	class FullscreenModelObserver;
	@class ToolbarsSize;

	// Represents the direction the user is scrolling.
	enum class FullscreenModelScrollDirection : int { kUp, kDown, kNone };

	// Model object used to calculate fullscreen state.
	class FullscreenModel : public ChromeBroadcastObserverInterface,
	ToolbarsSizeObserver {
	public:
	FullscreenModel();

	FullscreenModel(const FullscreenModel&) = delete;
	FullscreenModel& operator=(const FullscreenModel&) = delete;

	~FullscreenModel() override;

	// Adds and removes FullscreenModelObservers.
	void AddObserver(FullscreenModelObserver* observer);
	void RemoveObserver(FullscreenModelObserver* observer);

	// The progress value calculated by the model.
	CGFloat progress() const { return progress_; }

	// Whether fullscreen is disabled. When disabled, the toolbar is completely
	// visible.
	bool enabled() const { return disabled_counter_ == 0U; }

	// Whether the base offset has been recorded after state has been invalidated
	// by navigations or toolbar height changes.
	bool has_base_offset() const {
	CHECK(base::FeatureList::IsEnabled(web::features::kSmoothScrollingDefault));
	return !std::isnan(base_offset_);
	}

	// The base offset against which the fullscreen progress is being calculated.
	CGFloat base_offset() const { return base_offset_; }

	// Returns the difference between the max and min toolbar heights.
	CGFloat get_toolbar_height_delta() const {
	CGFloat top_delta =
	GetExpandedTopToolbarHeight() - GetCollapsedTopToolbarHeight();
	if (top_delta < FLT_EPSILON &&
	GetCollapsedBottomToolbarHeight() >= FLT_EPSILON) {
	CGFloat bottom_delta =
	GetExpandedBottomToolbarHeight() - GetCollapsedBottomToolbarHeight();
	return bottom_delta;
	}
	return top_delta;
	}

	// Returns whether the page content is tall enough for the toolbar to be
	// scrolled to an entirely collapsed position.
	bool can_collapse_toolbar() const {
	return content_height_ > scroll_view_height_ + get_toolbar_height_delta();
	}

	// Whether the view is scrolled all the way to the top.
	bool is_scrolled_to_top() const {
	return y_content_offset_ <= -GetExpandedTopToolbarHeight();
	}

	// Whether the view is scrolled all the way to the bottom.
	bool is_scrolled_to_bottom() const {
	if (base::FeatureList::IsEnabled(web::features::kSmoothScrollingDefault)) {
	return y_content_offset_ + scroll_view_height_ >= content_height_;
	} else {
	return y_content_offset_ -
	(GetCollapsedTopToolbarHeight() +
	GetCollapsedBottomToolbarHeight() + safe_area_insets_.bottom +
	safe_area_insets_.top) +
	(scroll_view_height_ + GetExpandedTopToolbarHeight() +
	GetExpandedBottomToolbarHeight()) >=
	content_height_;
	}
	}

	// The min, max, and current insets caused by the toolbars.
	UIEdgeInsets min_toolbar_insets() const {
	return GetToolbarInsetsAtProgress(0.0);
	}
	UIEdgeInsets max_toolbar_insets() const {
	return GetToolbarInsetsAtProgress(1.0);
	}
	UIEdgeInsets current_toolbar_insets() const {
	return GetToolbarInsetsAtProgress(progress_);
	}

	// Returns the toolbar insets at `progress`.
	UIEdgeInsets GetToolbarInsetsAtProgress(CGFloat progress) const {
	return UIEdgeInsetsMake(GetCollapsedTopToolbarHeight() +
	progress * (GetExpandedTopToolbarHeight() -
	GetCollapsedTopToolbarHeight()),
	0,
	GetCollapsedBottomToolbarHeight() +
	progress * (GetExpandedBottomToolbarHeight() -
	GetCollapsedBottomToolbarHeight()),
	0);
	}

	// Increments and decrements `disabled_counter_` for features that require the
	// toolbar be completely visible.
	void IncrementDisabledCounter();
	void DecrementDisabledCounter();

	// Force enter fullscreen without animation. Setting the progress to 0.0 even
	// when fullscreen is disabled.
	void ForceEnterFullscreen();

	// Recalculates the fullscreen progress for a new navigation.
	void ResetForNavigation();

	// Instructs the model to ignore broadcasted scroll updates for the remainder
	// of the current scroll. Has no effect if not called while a scroll is
	// occurring. The model will resume listening for scroll events when
	// `scrolling_` is reset to false.
	void IgnoreRemainderOfCurrentScroll();

	// Called when a scroll end animation finishes. `progress` is the fullscreen
	// progress corresponding to the final state of the aniamtion.
	void AnimationEndedWithProgress(CGFloat progress);

	// TODO(crbug.com/397683326): Move these values to `ToolbarsSize`.
	// Getter for the minimum top toolbar height to use in calculations.
	CGFloat GetCollapsedTopToolbarHeight() const;

	// Getter for the maximum top toolbar height to use in calculations.
	CGFloat GetExpandedTopToolbarHeight() const;

	// Getter for the maximum bottom toolbar height to use in calculations.
	CGFloat GetExpandedBottomToolbarHeight() const;

	// Getter for the minimum bottom toolbar height to use in calculations.
	CGFloat GetCollapsedBottomToolbarHeight() const;

	// Whenever the height of the top or bottom toolbar changes.
	void ToolbarsHeightDidChange();

	// Setter for the height of the scroll view displaying the main content.
	void SetScrollViewHeight(CGFloat scroll_view_height);
	CGFloat GetScrollViewHeight() const;

	// Setter for the current height of the rendered page.
	void SetContentHeight(CGFloat content_height);
	CGFloat GetContentHeight() const;

	// Setter for the top content inset of the scroll view displaying the main
	// content.
	void SetTopContentInset(CGFloat top_inset);
	CGFloat GetTopContentInset() const;

	// Setter for the current vertical content offset. Setting this will
	// recalculate the progress value.
	void SetYContentOffset(CGFloat y_content_offset);
	CGFloat GetYContentOffset() const;

	// Setter for whether the scroll view is scrolling. If a scroll event ends
	// and the progress value is not 0.0 or 1.0, the model will round to the
	// nearest value.
	void SetScrollViewIsScrolling(bool scrolling);
	bool IsScrollViewScrolling() const;

	// Setter for whether the scroll view is zooming.
	void SetScrollViewIsZooming(bool zooming);
	bool IsScrollViewZooming() const;

	// Setter for whether the scroll view is being dragged.
	void SetScrollViewIsDragging(bool dragging);
	bool IsScrollViewDragging() const;

	// Setter for whether the scroll view is resized for fullscreen events.
	void SetResizesScrollView(bool resizes_scroll_view);
	bool ResizesScrollView() const;

	// Setter for the safe area insets for the current WebState's view.
	void SetWebViewSafeAreaInsets(UIEdgeInsets safe_area_insets);
	UIEdgeInsets GetWebViewSafeAreaInsets() const;

	// Setter for whether force fullscreen mode is active. The mode is used when
	// the bottom toolbar is collapsed above the keyboard.
	void SetForceFullscreenMode(bool force_fullscreen_mode);
	bool IsForceFullscreenMode() const;
	void SetInsetsUpdateEnabled(bool enabled);
	bool IsInsetsUpdateEnabled() const;

	FullscreenModelScrollDirection GetLastScrollDirection() const {
	return fullscreen_scroll_direction_;
	}

	// Sets the last scroll direction. If the direction has changed, the base
	// offset is updated.
	void SetLastScrollDirection(FullscreenModelScrollDirection direction);

	// Updates `speed_` of the fullscreen model accordingly to
	// fullscreen flag `fullscreen transition experiment`.
	void UpdateSpeed();

	// Getter for the speed of fullscren transition.
	CGFloat GetSpeed() { return speed_; }

	// Setter for the toolbar.
	void SetToolbarsSize(ToolbarsSize* toolbars_size);

	private:
	// Returns how a scroll to the current `y_content_offset_` from `from_offset`
	// should be handled.
	enum class ScrollAction : short {
	kIgnore, // Ignore the scroll.
	kUpdateBaseOffset, // Update `base_offset_` only.
	kUpdateProgress, // Update `progress_` only.
	kUpdateBaseOffsetAndProgress, // Update `base_offset_` and `progress_`.
	};
	ScrollAction ActionForScrollFromOffset(CGFloat from_offset) const;

	// Updates the base offset given the current y content offset, progress, and
	// toolbar height.
	void UpdateBaseOffset();

	// Updates the progress value given the current y content offset, base offset,
	// and toolbar height.
	void UpdateProgress();

	// Updates the disabled counter depending on the current values of
	// `scroll_view_height_` and `content_height_`.
	void UpdateDisabledCounterForContentHeight();

	// Setter for `progress_`. Notifies observers of the new value if
	// `notify_observers` is true.
	void SetProgress(CGFloat progress);

	// Returns true if the size of the scroll is more than the threshold to begin
	// entering or exiting fullscreen.
	bool ScrollThresholdExceeded() const;

	// ChromeBroadcastObserverInterface:
	void OnScrollViewSizeBroadcasted(CGSize scroll_view_size) override;
	void OnScrollViewContentSizeBroadcasted(CGSize content_size) override;
	void OnScrollViewContentInsetBroadcasted(UIEdgeInsets content_inset) override;
	void OnContentScrollOffsetBroadcasted(CGFloat offset) override;
	void OnScrollViewIsScrollingBroadcasted(bool scrolling) override;
	void OnScrollViewIsZoomingBroadcasted(bool zooming) override;
	void OnScrollViewIsDraggingBroadcasted(bool dragging) override;
	void OnCollapsedTopToolbarHeightBroadcasted(CGFloat height) override;
	void OnExpandedTopToolbarHeightBroadcasted(CGFloat height) override;
	void OnExpandedBottomToolbarHeightBroadcasted(CGFloat height) override;
	void OnCollapsedBottomToolbarHeightBroadcasted(CGFloat height) override;

	// ToolbarsSizeObserver implementation
	void OnTopToolbarHeightChanged() override;
	void OnBottomToolbarHeightChanged() override;
	// The observers for this model.
	base::ObserverList<FullscreenModelObserver, true> observers_;
	// The percentage of the toolbar that should be visible, where 1.0 denotes a
	// fully visible toolbar and 0.0 denotes a completely hidden one.
	CGFloat progress_ = 0.0;
	// The base offset from which to calculate fullscreen state. When `locked_`
	// is false, it is reset to the current offset after each scroll event.
	CGFloat base_offset_ = 0.0;
	// Heights of the top and bottom toolbars.
	ToolbarsSize* toolbars_size_;
	// The current vertical content offset of the main content.
	CGFloat y_content_offset_ = 0.0;
	// The height of the scroll view displaying the current page.
	CGFloat scroll_view_height_ = 0.0;
	// The height of the current page's rendered content.
	CGFloat content_height_ = 0.0;
	// The top inset of the scroll view displaying the current page.
	CGFloat top_inset_ = 0.0;
	// How many currently-running features require the toolbar be visible.
	size_t disabled_counter_ = 0;
	// Counts the number of currently-running feature that require to force
	// fullscreen mode.
	size_t force_fullscreen_mode_counter_ = 0;
	// Whether fullscreen is disabled for short content.
	bool disabled_for_short_content_ = false;
	// Whether the main content is being scrolled.
	bool scrolling_ = false;
	// Whether the scroll view is zooming.
	bool zooming_ = false;
	// Whether the main content is being dragged.
	bool dragging_ = false;
	// Whether the in-progress scroll is being ignored.
	bool ignoring_current_scroll_ = false;
	// Whether the scroll view is resized for fullscreen events.
	bool resizes_scroll_view_ = false;
	// The WebState view's safe area insets.
	UIEdgeInsets safe_area_insets_ = UIEdgeInsetsZero;
	// The number of FullscreenModelObserver callbacks currently being executed.
	size_t observer_callback_count_ = 0;
	// Whether updating insets is enabled.
	bool insets_update_enabled_ = true;
	// Whether progress is currently being set.
	bool setting_progress_ = false;
	// Current direction of scrolling initiated by the user.
	FullscreenModelScrollDirection fullscreen_scroll_direction_ =
	FullscreenModelScrollDirection::kNone;
	// Speed of fullscreen transition.
	CGFloat speed_ = 1.0;
	// Time when scrolling started.
	std::optional<base::TimeTicks> start_scrolling_time_ = std::nullopt;
	// True is the scrolling time have been recorded.
	bool is_scrolling_time_recorded_ = false;
	// The minimum scroll amount that will result in beginning to enter or exit
	// fullscreen.
	CGFloat scroll_threshold_ = 0.0;
	// The content offset when the most recent drag event started.
	CGFloat offset_at_start_of_drag_ = 0;

	friend class FullscreenModelTest;
	};

	#endif // IOS_CHROME_BROWSER_FULLSCREEN_UI_BUNDLED_FULLSCREEN_MODEL_H_