content/common/render_frame_metadata.mojom

// Copyright 2018 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.

module content.mojom;

import "mojo/public/mojom/base/time.mojom";
import "services/viz/public/mojom/compositing/local_surface_id_allocation.mojom";
import "services/viz/public/mojom/compositing/selection.mojom";
import "services/viz/public/mojom/compositing/vertical_scroll_direction.mojom";
import "ui/gfx/geometry/mojom/geometry.mojom";

// See components/viz/service/quads/render_frame_metadata.h
struct RenderFrameMetadata {
  // The background color of a CompositorFrame. It can be used for filling the
  // content area if the primary surface is unavailable and fallback is not
  // specified.
  uint32 root_background_color;

  // Scroll offset of the root layer. This optional parameter is only sent
  // during tests.
  gfx.mojom.Vector2dF? root_scroll_offset;

  // Indicates whether the scroll offset of the root layer is at top, i.e.,
  // whether scroll_offset.y() == 0.
  bool is_scroll_offset_at_top;

  // Selection region relative to the current viewport. If the selection is
  // empty or otherwise unused, the bound types will indicate such.
  viz.mojom.Selection selection;

  // Determines whether the page is mobile optimized or not, which means at
  // least one of the following has to be true:
  // - page has a width=device-width or narrower viewport.
  // - page prevents zooming in or out (i.e. min and max page scale factors
  // are the same).
  bool is_mobile_optimized;

  // The device scale factor used to generate CompositorFrame.
  float device_scale_factor;

  // The size of the viewport used to generate a CompositorFrame.
  gfx.mojom.Size viewport_size_in_pixels;

  // The last viz::LocalSurfaceIdAllocation used to submit a CompositorFrame.
  viz.mojom.LocalSurfaceIdAllocation? local_surface_id_allocation;

  // The page scale factor used on the content.
  float page_scale_factor;

  // The subframe page scale factor used on the content. This value will match
  // |page_scale_factor|, which is only ever set for the main frame, and it is
  // only used for setting raster scale in child renderers.
  float external_page_scale_factor;

  // Used to position the Android location top bar and page content, whose
  // precise position is computed by the renderer compositor.
  float top_controls_height;

  float top_controls_shown_ratio;

  viz.mojom.VerticalScrollDirection new_vertical_scroll_direction;

  // Used to position Android bottom bar, whose position is computed by the
  // renderer compositor.
  [EnableIf=is_android]
  float bottom_controls_height;

  [EnableIf=is_android]
  float bottom_controls_shown_ratio;

  [EnableIf=is_android]
  float top_controls_min_height_offset;

  [EnableIf=is_android]
  float bottom_controls_min_height_offset;

  [EnableIf=is_android]
  float min_page_scale_factor;

  [EnableIf=is_android]
  float max_page_scale_factor;

  [EnableIf=is_android]
  bool root_overflow_y_hidden;

  [EnableIf=is_android]
  gfx.mojom.SizeF scrollable_viewport_size;

  [EnableIf=is_android]
  gfx.mojom.SizeF root_layer_size;

  [EnableIf=is_android]
  bool has_transparent_background;
};

// This interface is provided by the renderer. It impacts the frequency with
// which a fully populated RenderFrameMetadata object (above) is delivered to
// the RenderFrameMetadataObserverClient.
interface RenderFrameMetadataObserver {
  // When |enabled| is set to true, this will send RenderFrameMetadata to
  // the RenderFrameMetadataObserverClient for any frame in which the root
  // scroll changes. Used only on Android for accessibility cases.
  [EnableIf=is_android]
  ReportAllRootScrollsForAccessibility(bool enabled);
  // When |enabled| is set to true, this will send RenderFrameMetadata to
  // the RenderFrameMetadataObserverClient for all frames. Only used for
  // tests.
  ReportAllFrameSubmissionsForTesting(bool enabled);
};

// This interface is provided by the browser. It is notified of changes to
// RenderFrameMetadata. It can be notified of all frame submissions, via
// RenderFrameMetadataObserver::ReportAllFrameSubmissionsForTesting, or of
// additional frames with root scroll offset changes via
// RenderFrameMetadataObserver::ReportAllRootScrollsForAccessibility.
interface RenderFrameMetadataObserverClient {
  // Notified when RenderFrameMetadata has changed.
  OnRenderFrameMetadataChanged(uint32 frame_token, RenderFrameMetadata metadata);

  // Notified on all frame submissions.
  OnFrameSubmissionForTesting(uint32 frame_token);
};