content/browser/renderer_host/input/composited_scrolling_browsertest.cc - experimental/chromium/src - Git at Google

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #include <utility>

 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/macros.h"
 #include "base/run_loop.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/metrics/histogram_tester.h"
 #include "base/test/scoped_feature_list.h"
 #include "build/build_config.h"
 #include "cc/base/features.h"
 #include "content/browser/renderer_host/input/synthetic_gesture.h"
 #include "content/browser/renderer_host/input/synthetic_smooth_scroll_gesture.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/common/input/synthetic_gesture_params.h"
 #include "content/common/input/synthetic_smooth_scroll_gesture_params.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/test/browser_test.h"
 #include "content/public/test/browser_test_utils.h"
 #include "content/public/test/content_browser_test.h"
 #include "content/public/test/content_browser_test_utils.h"
 #include "content/public/test/hit_test_region_observer.h"
 #include "content/public/test/test_utils.h"
 #include "content/shell/browser/shell.h"
 #include "third_party/blink/public/common/switches.h"
 #include "ui/gfx/geometry/angle_conversions.h"

 namespace {

 const char kCompositedScrollingDataURL[] =
     "data:text/html;charset=utf-8,"
     "<!DOCTYPE html>"
     "<meta name='viewport' content='width=device-width'/>"
     "<style>"
     "%23scroller {"
     "  width:500px;"
     "  height:500px;"
     "  overflow:scroll;"
     "  transform: rotateX(-30deg);"
     "}"

     "%23content {"
     "  background-color:red;"
     "  width:1000px;"
     "  height:1000px;"
     "}"
     "</style>"
     "<div id='scroller'>"
     "  <div id='content'>"
     "  </div>"
     "</div>"
     "<script>"
     "  document.title='ready';"
     "</script>";

 }  // namespace

 namespace content {


 class CompositedScrollingBrowserTest : public ContentBrowserTest {
  public:
   CompositedScrollingBrowserTest() {
     // Disable scroll resampling because this is checking scroll distance.
     scoped_feature_list_.InitAndDisableFeature(
         blink::features::kResamplingScrollEvents);
   }

   ~CompositedScrollingBrowserTest() override = default;

   void SetUpCommandLine(base::CommandLine* cmd) override {
     cmd->AppendSwitch(blink::switches::kEnablePreferCompositingToLCDText);
   }

   RenderWidgetHostImpl* GetWidgetHost() {
     return RenderWidgetHostImpl::From(shell()
                                           ->web_contents()
                                           ->GetMainFrame()
                                           ->GetRenderViewHost()
                                           ->GetWidget());
   }

   void OnSyntheticGestureCompleted(SyntheticGesture::Result result) {
     EXPECT_EQ(SyntheticGesture::GESTURE_FINISHED, result);
     runner_->Quit();
   }

  protected:
   void LoadURL(const char* url) {
     const GURL data_url(url);
     EXPECT_TRUE(NavigateToURL(shell(), data_url));

     RenderWidgetHostImpl* host = GetWidgetHost();
     HitTestRegionObserver observer(GetWidgetHost()->GetFrameSinkId());
     host->GetView()->SetSize(gfx::Size(400, 400));

     std::u16string ready_title(u"ready");
     TitleWatcher watcher(shell()->web_contents(), ready_title);
     ignore_result(watcher.WaitAndGetTitle());

     // Wait for the hit test data to be ready after initiating URL loading
     // before returning
     observer.WaitForHitTestData();
   }

   // ContentBrowserTest:
   int ExecuteScriptAndExtractInt(const std::string& script) {
     int value = 0;
     EXPECT_TRUE(content::ExecuteScriptAndExtractInt(
         shell(), "domAutomationController.send(" + script + ")", &value));
     return value;
   }

   double ExecuteScriptAndExtractDouble(const std::string& script) {
     double value = 0;
     EXPECT_TRUE(content::ExecuteScriptAndExtractDouble(
         shell(), "domAutomationController.send(" + script + ")", &value));
     return value;
   }

   double GetScrollTop() {
     return ExecuteScriptAndExtractDouble(
         "document.getElementById(\"scroller\").scrollTop");
   }

   // Generate touch events for a synthetic scroll from |point| for |distance|.
   // Returns the distance scrolled.
   double DoScroll(content::mojom::GestureSourceType type,
                   const gfx::Point& point,
                   const gfx::Vector2d& distance) {
     SyntheticSmoothScrollGestureParams params;
     params.gesture_source_type = type;
     params.anchor = gfx::PointF(point);
     params.distances.push_back(-distance);

     runner_ = new MessageLoopRunner();

     std::unique_ptr<SyntheticSmoothScrollGesture> gesture(
         new SyntheticSmoothScrollGesture(params));
     GetWidgetHost()->QueueSyntheticGesture(
         std::move(gesture),
         base::BindOnce(
             &CompositedScrollingBrowserTest::OnSyntheticGestureCompleted,
             base::Unretained(this)));

     // Runs until we get the OnSyntheticGestureCompleted callback
     runner_->Run();
     runner_ = nullptr;

     return GetScrollTop();
   }

   double DoTouchScroll(const gfx::Point& point, const gfx::Vector2d& distance) {
     return DoScroll(content::mojom::GestureSourceType::kTouchInput, point,
                     distance);
   }

   double DoWheelScroll(const gfx::Point& point, const gfx::Vector2d& distance) {
     return DoScroll(content::mojom::GestureSourceType::kMouseInput, point,
                     distance);
   }

  private:
   base::test::ScopedFeatureList scoped_feature_list_;
   scoped_refptr<MessageLoopRunner> runner_;

   DISALLOW_COPY_AND_ASSIGN(CompositedScrollingBrowserTest);
 };

 // Verify transforming a scroller doesn't prevent it from scrolling. See
 // crbug.com/543655 for a case where this was broken.
 // Disabled on MacOS because it doesn't support touch input.
 // Disabled on Android due to flakiness, see https://crbug.com/376668.
 // Flaky on Windows: crbug.com/804009
 #if defined(OS_MAC) || defined(OS_ANDROID) || defined(OS_WIN)
 #define MAYBE_Scroll3DTransformedScroller DISABLED_Scroll3DTransformedScroller
 #else
 #define MAYBE_Scroll3DTransformedScroller Scroll3DTransformedScroller
 #endif
 IN_PROC_BROWSER_TEST_F(CompositedScrollingBrowserTest,
                        MAYBE_Scroll3DTransformedScroller) {
   LoadURL(kCompositedScrollingDataURL);
   ASSERT_EQ(0, GetScrollTop());

   double scroll_distance =
       DoTouchScroll(gfx::Point(50, 150), gfx::Vector2d(0, 100));
   // The scroll distance is increased due to the rotation of the scroller.
   EXPECT_NEAR(100 / std::cos(gfx::DegToRad(30.f)), scroll_distance, 1.f);
 }

 class CompositedScrollingMetricTest : public CompositedScrollingBrowserTest,
                                       public testing::WithParamInterface<bool> {
  public:
   CompositedScrollingMetricTest() = default;
   ~CompositedScrollingMetricTest() override = default;

   void SetUpCommandLine(base::CommandLine* cmd) override {
     const bool enable_composited_scrolling = GetParam();
     if (enable_composited_scrolling)
       cmd->AppendSwitch(blink::switches::kEnablePreferCompositingToLCDText);
     else
       cmd->AppendSwitch(blink::switches::kDisableThreadedScrolling);
   }

   bool CompositingEnabled() { return GetParam(); }

   const char* kWheelHistogramName = "Renderer4.ScrollingThread.Wheel";
   const char* kTouchHistogramName = "Renderer4.ScrollingThread.Touch";

   // These values are defined in input_handler_proxy.cc and match the enum in
   // histograms.xml.
   enum ScrollingThreadStatus {
     kScrollingOnCompositor = 0,
     kScrollingOnCompositorBlockedOnMain = 1,
     kScrollingOnMain = 2,
     kMaxValue = kScrollingOnMain,
   };
 };

 INSTANTIATE_TEST_SUITE_P(All,
                          CompositedScrollingMetricTest,
                          ::testing::Bool());

 // Tests the functionality of the histogram tracking composited vs main thread
 // scrolls.
 IN_PROC_BROWSER_TEST_P(CompositedScrollingMetricTest,
                        RecordCorrectScrollingThread) {
   LoadURL(R"HTML(
     data:text/html;charset=utf-8,
     <!DOCTYPE html>
     <style>
       %23scroller {
         width: 300px;
         height: 300px;
         overflow: auto;
       }
       %23space {
         width: 1000px;
         height: 1000px;
       }
     </style>
     <div id='scroller'>
       <div id='space'></div>
     </div>
     <script>
       document.title = 'ready';
     </script>
   )HTML");

   base::HistogramTester histograms;

   DoTouchScroll(gfx::Point(50, 50), gfx::Vector2d(0, 100));
   DoTouchScroll(gfx::Point(50, 50), gfx::Vector2d(0, -100));

   DoWheelScroll(gfx::Point(50, 50), gfx::Vector2d(0, 100));

   content::FetchHistogramsFromChildProcesses();

   base::HistogramBase::Sample expected_bucket =
       CompositingEnabled() ? kScrollingOnCompositor : kScrollingOnMain;
   if (base::FeatureList::IsEnabled(::features::kScrollUnification)) {
     // TODO: crbug.com/1082590
     // After ScrollUnification all scrolls happen on the compositor thread
     // but some will still force blocking on main thread
     expected_bucket = kScrollingOnCompositor;
   }

   histograms.ExpectUniqueSample(kTouchHistogramName, expected_bucket, 2);
   histograms.ExpectUniqueSample(kWheelHistogramName, expected_bucket, 1);
 }

 // Tests the composited vs main thread scrolling histogram in the presence of
 // blocking event handlers.
 IN_PROC_BROWSER_TEST_P(CompositedScrollingMetricTest, BlockingEventHandlers) {
   LoadURL(R"HTML(
     data:text/html;charset=utf-8,
     <!DOCTYPE html>
     <style>
       %23scroller {
         width: 300px;
         height: 300px;
         overflow: auto;
       }
       %23space {
         width: 1000px;
         height: 1000px;
       }
     </style>
     <div id='scroller'>
       <div id='space'></div>
     </div>
     <script>
       const scroller = document.getElementById('scroller');
       scroller.addEventListener('wheel', (e) => { }, {passive: false});
       scroller.addEventListener('touchstart', (e) => { }, {passive: false});
       onload = () => {
         document.title = 'ready';
       }
     </script>
   )HTML");

   base::HistogramTester histograms;

   DoTouchScroll(gfx::Point(50, 50), gfx::Vector2d(0, 100));
   DoTouchScroll(gfx::Point(50, 50), gfx::Vector2d(0, -100));

   DoWheelScroll(gfx::Point(50, 50), gfx::Vector2d(0, 100));

   content::FetchHistogramsFromChildProcesses();

   base::HistogramBase::Sample expected_bucket =
       CompositingEnabled() ? kScrollingOnCompositorBlockedOnMain
                            : kScrollingOnMain;
   if (base::FeatureList::IsEnabled(::features::kScrollUnification)) {
     // TODO: crbug.com/1082590
     // After ScrollUnification all scrolls happen on the compositor thread
     // but some will still force blocking on main thread
     expected_bucket = kScrollingOnCompositorBlockedOnMain;
   }

   histograms.ExpectUniqueSample(kTouchHistogramName, expected_bucket, 2);
   histograms.ExpectUniqueSample(kWheelHistogramName, expected_bucket, 1);
 }

 // Tests the composited vs main thread scrolling histogram in the presence of
 // passive event handlers. These should behave the same as the case without any
 // event handlers at all.
 IN_PROC_BROWSER_TEST_P(CompositedScrollingMetricTest, PassiveEventHandlers) {
   LoadURL(R"HTML(
     data:text/html;charset=utf-8,
     <!DOCTYPE html>
     <style>
       %23scroller {
         width: 300px;
         height: 300px;
         overflow: auto;
       }
       %23space {
         width: 1000px;
         height: 1000px;
       }
     </style>
     <div id='scroller'>
       <div id='space'></div>
     </div>
     <script>
       const scroller = document.getElementById('scroller');
       scroller.addEventListener('wheel', (e) => { }, {passive: true});
       scroller.addEventListener('touchstart', (e) => { }, {passive: true});
       onload = () => {
         document.title = 'ready';
       }
     </script>
   )HTML");

   base::HistogramTester histograms;

   DoTouchScroll(gfx::Point(50, 50), gfx::Vector2d(0, 100));
   DoTouchScroll(gfx::Point(50, 50), gfx::Vector2d(0, -100));

   DoWheelScroll(gfx::Point(50, 50), gfx::Vector2d(0, 100));

   content::FetchHistogramsFromChildProcesses();

   base::HistogramBase::Sample expected_bucket =
       CompositingEnabled() ? kScrollingOnCompositor : kScrollingOnMain;
   if (base::FeatureList::IsEnabled(::features::kScrollUnification)) {
     // TODO: crbug.com/1082590
     // After ScrollUnification all scrolls happen on the compositor thread
     // but some will still force blocking on main thread
     expected_bucket = kScrollingOnCompositor;
   }

   histograms.ExpectUniqueSample(kTouchHistogramName, expected_bucket, 2);
   histograms.ExpectUniqueSample(kWheelHistogramName, expected_bucket, 1);
 }

 }  // namespace content
	// Copyright 2015 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#include <utility>

	#include "base/bind.h"
	#include "base/command_line.h"
	#include "base/macros.h"
	#include "base/run_loop.h"
	#include "base/strings/utf_string_conversions.h"
	#include "base/test/metrics/histogram_tester.h"
	#include "base/test/scoped_feature_list.h"
	#include "build/build_config.h"
	#include "cc/base/features.h"
	#include "content/browser/renderer_host/input/synthetic_gesture.h"
	#include "content/browser/renderer_host/input/synthetic_smooth_scroll_gesture.h"
	#include "content/browser/renderer_host/render_widget_host_impl.h"
	#include "content/browser/web_contents/web_contents_impl.h"
	#include "content/common/input/synthetic_gesture_params.h"
	#include "content/common/input/synthetic_smooth_scroll_gesture_params.h"
	#include "content/public/browser/render_view_host.h"
	#include "content/public/common/content_switches.h"
	#include "content/public/test/browser_test.h"
	#include "content/public/test/browser_test_utils.h"
	#include "content/public/test/content_browser_test.h"
	#include "content/public/test/content_browser_test_utils.h"
	#include "content/public/test/hit_test_region_observer.h"
	#include "content/public/test/test_utils.h"
	#include "content/shell/browser/shell.h"
	#include "third_party/blink/public/common/switches.h"
	#include "ui/gfx/geometry/angle_conversions.h"

	namespace {

	const char kCompositedScrollingDataURL[] =
	"data:text/html;charset=utf-8,"
	"<!DOCTYPE html>"
	"<meta name='viewport' content='width=device-width'/>"
	"<style>"
	"%23scroller {"
	" width:500px;"
	" height:500px;"
	" overflow:scroll;"
	" transform: rotateX(-30deg);"
	"}"

	"%23content {"
	" background-color:red;"
	" width:1000px;"
	" height:1000px;"
	"}"
	"</style>"
	"<div id='scroller'>"
	" <div id='content'>"
	" </div>"
	"</div>"
	"<script>"
	" document.title='ready';"
	"</script>";

	} // namespace

	namespace content {


	class CompositedScrollingBrowserTest : public ContentBrowserTest {
	public:
	CompositedScrollingBrowserTest() {
	// Disable scroll resampling because this is checking scroll distance.
	scoped_feature_list_.InitAndDisableFeature(
	blink::features::kResamplingScrollEvents);
	}

	~CompositedScrollingBrowserTest() override = default;

	void SetUpCommandLine(base::CommandLine* cmd) override {
	cmd->AppendSwitch(blink::switches::kEnablePreferCompositingToLCDText);
	}

	RenderWidgetHostImpl* GetWidgetHost() {
	return RenderWidgetHostImpl::From(shell()
	->web_contents()
	->GetMainFrame()
	->GetRenderViewHost()
	->GetWidget());
	}

	void OnSyntheticGestureCompleted(SyntheticGesture::Result result) {
	EXPECT_EQ(SyntheticGesture::GESTURE_FINISHED, result);
	runner_->Quit();
	}

	protected:
	void LoadURL(const char* url) {
	const GURL data_url(url);
	EXPECT_TRUE(NavigateToURL(shell(), data_url));

	RenderWidgetHostImpl* host = GetWidgetHost();
	HitTestRegionObserver observer(GetWidgetHost()->GetFrameSinkId());
	host->GetView()->SetSize(gfx::Size(400, 400));

	std::u16string ready_title(u"ready");
	TitleWatcher watcher(shell()->web_contents(), ready_title);
	ignore_result(watcher.WaitAndGetTitle());

	// Wait for the hit test data to be ready after initiating URL loading
	// before returning
	observer.WaitForHitTestData();
	}

	// ContentBrowserTest:
	int ExecuteScriptAndExtractInt(const std::string& script) {
	int value = 0;
	EXPECT_TRUE(content::ExecuteScriptAndExtractInt(
	shell(), "domAutomationController.send(" + script + ")", &value));
	return value;
	}

	double ExecuteScriptAndExtractDouble(const std::string& script) {
	double value = 0;
	EXPECT_TRUE(content::ExecuteScriptAndExtractDouble(
	shell(), "domAutomationController.send(" + script + ")", &value));
	return value;
	}

	double GetScrollTop() {
	return ExecuteScriptAndExtractDouble(
	"document.getElementById(\"scroller\").scrollTop");
	}

	// Generate touch events for a synthetic scroll from \|point\| for \|distance\|.
	// Returns the distance scrolled.
	double DoScroll(content::mojom::GestureSourceType type,
	const gfx::Point& point,
	const gfx::Vector2d& distance) {
	SyntheticSmoothScrollGestureParams params;
	params.gesture_source_type = type;
	params.anchor = gfx::PointF(point);
	params.distances.push_back(-distance);

	runner_ = new MessageLoopRunner();

	std::unique_ptr<SyntheticSmoothScrollGesture> gesture(
	new SyntheticSmoothScrollGesture(params));
	GetWidgetHost()->QueueSyntheticGesture(
	std::move(gesture),
	base::BindOnce(
	&CompositedScrollingBrowserTest::OnSyntheticGestureCompleted,
	base::Unretained(this)));

	// Runs until we get the OnSyntheticGestureCompleted callback
	runner_->Run();
	runner_ = nullptr;

	return GetScrollTop();
	}

	double DoTouchScroll(const gfx::Point& point, const gfx::Vector2d& distance) {
	return DoScroll(content::mojom::GestureSourceType::kTouchInput, point,
	distance);
	}

	double DoWheelScroll(const gfx::Point& point, const gfx::Vector2d& distance) {
	return DoScroll(content::mojom::GestureSourceType::kMouseInput, point,
	distance);
	}

	private:
	base::test::ScopedFeatureList scoped_feature_list_;
	scoped_refptr<MessageLoopRunner> runner_;

	DISALLOW_COPY_AND_ASSIGN(CompositedScrollingBrowserTest);
	};

	// Verify transforming a scroller doesn't prevent it from scrolling. See
	// crbug.com/543655 for a case where this was broken.
	// Disabled on MacOS because it doesn't support touch input.
	// Disabled on Android due to flakiness, see https://crbug.com/376668.
	// Flaky on Windows: crbug.com/804009
	#if defined(OS_MAC) \|\| defined(OS_ANDROID) \|\| defined(OS_WIN)
	#define MAYBE_Scroll3DTransformedScroller DISABLED_Scroll3DTransformedScroller
	#else
	#define MAYBE_Scroll3DTransformedScroller Scroll3DTransformedScroller
	#endif
	IN_PROC_BROWSER_TEST_F(CompositedScrollingBrowserTest,
	MAYBE_Scroll3DTransformedScroller) {
	LoadURL(kCompositedScrollingDataURL);
	ASSERT_EQ(0, GetScrollTop());

	double scroll_distance =
	DoTouchScroll(gfx::Point(50, 150), gfx::Vector2d(0, 100));
	// The scroll distance is increased due to the rotation of the scroller.
	EXPECT_NEAR(100 / std::cos(gfx::DegToRad(30.f)), scroll_distance, 1.f);
	}

	class CompositedScrollingMetricTest : public CompositedScrollingBrowserTest,
	public testing::WithParamInterface<bool> {
	public:
	CompositedScrollingMetricTest() = default;
	~CompositedScrollingMetricTest() override = default;

	void SetUpCommandLine(base::CommandLine* cmd) override {
	const bool enable_composited_scrolling = GetParam();
	if (enable_composited_scrolling)
	cmd->AppendSwitch(blink::switches::kEnablePreferCompositingToLCDText);
	else
	cmd->AppendSwitch(blink::switches::kDisableThreadedScrolling);
	}

	bool CompositingEnabled() { return GetParam(); }

	const char* kWheelHistogramName = "Renderer4.ScrollingThread.Wheel";
	const char* kTouchHistogramName = "Renderer4.ScrollingThread.Touch";

	// These values are defined in input_handler_proxy.cc and match the enum in
	// histograms.xml.
	enum ScrollingThreadStatus {
	kScrollingOnCompositor = 0,
	kScrollingOnCompositorBlockedOnMain = 1,
	kScrollingOnMain = 2,
	kMaxValue = kScrollingOnMain,
	};
	};

	INSTANTIATE_TEST_SUITE_P(All,
	CompositedScrollingMetricTest,
	::testing::Bool());

	// Tests the functionality of the histogram tracking composited vs main thread
	// scrolls.
	IN_PROC_BROWSER_TEST_P(CompositedScrollingMetricTest,
	RecordCorrectScrollingThread) {
	LoadURL(R"HTML(
	data:text/html;charset=utf-8,
	<!DOCTYPE html>
	<style>
	%23scroller {
	width: 300px;
	height: 300px;
	overflow: auto;
	}
	%23space {
	width: 1000px;
	height: 1000px;
	}
	</style>
	<div id='scroller'>
	<div id='space'></div>
	</div>
	<script>
	document.title = 'ready';
	</script>
	)HTML");

	base::HistogramTester histograms;

	DoTouchScroll(gfx::Point(50, 50), gfx::Vector2d(0, 100));
	DoTouchScroll(gfx::Point(50, 50), gfx::Vector2d(0, -100));

	DoWheelScroll(gfx::Point(50, 50), gfx::Vector2d(0, 100));

	content::FetchHistogramsFromChildProcesses();

	base::HistogramBase::Sample expected_bucket =
	CompositingEnabled() ? kScrollingOnCompositor : kScrollingOnMain;
	if (base::FeatureList::IsEnabled(::features::kScrollUnification)) {
	// TODO: crbug.com/1082590
	// After ScrollUnification all scrolls happen on the compositor thread
	// but some will still force blocking on main thread
	expected_bucket = kScrollingOnCompositor;
	}

	histograms.ExpectUniqueSample(kTouchHistogramName, expected_bucket, 2);
	histograms.ExpectUniqueSample(kWheelHistogramName, expected_bucket, 1);
	}

	// Tests the composited vs main thread scrolling histogram in the presence of
	// blocking event handlers.
	IN_PROC_BROWSER_TEST_P(CompositedScrollingMetricTest, BlockingEventHandlers) {
	LoadURL(R"HTML(
	data:text/html;charset=utf-8,
	<!DOCTYPE html>
	<style>
	%23scroller {
	width: 300px;
	height: 300px;
	overflow: auto;
	}
	%23space {
	width: 1000px;
	height: 1000px;
	}
	</style>
	<div id='scroller'>
	<div id='space'></div>
	</div>
	<script>
	const scroller = document.getElementById('scroller');
	scroller.addEventListener('wheel', (e) => { }, {passive: false});
	scroller.addEventListener('touchstart', (e) => { }, {passive: false});
	onload = () => {
	document.title = 'ready';
	}
	</script>
	)HTML");

	base::HistogramTester histograms;

	DoTouchScroll(gfx::Point(50, 50), gfx::Vector2d(0, 100));
	DoTouchScroll(gfx::Point(50, 50), gfx::Vector2d(0, -100));

	DoWheelScroll(gfx::Point(50, 50), gfx::Vector2d(0, 100));

	content::FetchHistogramsFromChildProcesses();

	base::HistogramBase::Sample expected_bucket =
	CompositingEnabled() ? kScrollingOnCompositorBlockedOnMain
	: kScrollingOnMain;
	if (base::FeatureList::IsEnabled(::features::kScrollUnification)) {
	// TODO: crbug.com/1082590
	// After ScrollUnification all scrolls happen on the compositor thread
	// but some will still force blocking on main thread
	expected_bucket = kScrollingOnCompositorBlockedOnMain;
	}

	histograms.ExpectUniqueSample(kTouchHistogramName, expected_bucket, 2);
	histograms.ExpectUniqueSample(kWheelHistogramName, expected_bucket, 1);
	}

	// Tests the composited vs main thread scrolling histogram in the presence of
	// passive event handlers. These should behave the same as the case without any
	// event handlers at all.
	IN_PROC_BROWSER_TEST_P(CompositedScrollingMetricTest, PassiveEventHandlers) {
	LoadURL(R"HTML(
	data:text/html;charset=utf-8,
	<!DOCTYPE html>
	<style>
	%23scroller {
	width: 300px;
	height: 300px;
	overflow: auto;
	}
	%23space {
	width: 1000px;
	height: 1000px;
	}
	</style>
	<div id='scroller'>
	<div id='space'></div>
	</div>
	<script>
	const scroller = document.getElementById('scroller');
	scroller.addEventListener('wheel', (e) => { }, {passive: true});
	scroller.addEventListener('touchstart', (e) => { }, {passive: true});
	onload = () => {
	document.title = 'ready';
	}
	</script>
	)HTML");

	base::HistogramTester histograms;

	DoTouchScroll(gfx::Point(50, 50), gfx::Vector2d(0, 100));
	DoTouchScroll(gfx::Point(50, 50), gfx::Vector2d(0, -100));

	DoWheelScroll(gfx::Point(50, 50), gfx::Vector2d(0, 100));

	content::FetchHistogramsFromChildProcesses();

	base::HistogramBase::Sample expected_bucket =
	CompositingEnabled() ? kScrollingOnCompositor : kScrollingOnMain;
	if (base::FeatureList::IsEnabled(::features::kScrollUnification)) {
	// TODO: crbug.com/1082590
	// After ScrollUnification all scrolls happen on the compositor thread
	// but some will still force blocking on main thread
	expected_bucket = kScrollingOnCompositor;
	}

	histograms.ExpectUniqueSample(kTouchHistogramName, expected_bucket, 2);
	histograms.ExpectUniqueSample(kWheelHistogramName, expected_bucket, 1);
	}

	} // namespace content