Surface synchronization: Plumb has_transparent_background

This CL plumbs the has_transparent_background bit through RenderFrameMetadata
on android when surface synchronization is enabled. This enables the correct
background color to be displayed when surface sync is on on android.

Bug: 672962
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: Id8ca61371cbe04a7ea58fbbf255bf80f6208e2b8
Reviewed-on: https://chromium-review.googlesource.com/1100065
Commit-Queue: Fady Samuel <fsamuel@chromium.org>
Reviewed-by: Saman Sami <samans@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567080}

cc/trees/layer_tree_host_impl.cc

@@ -1917,7 +1917,8 @@ viz::CompositorFrameMetadata LayerTreeHostImpl::MakeCompositorFrameMetadata() {
   return metadata;
 }
 
-RenderFrameMetadata LayerTreeHostImpl::MakeRenderFrameMetadata() {
+RenderFrameMetadata LayerTreeHostImpl::MakeRenderFrameMetadata(
+    FrameData* frame) {
   RenderFrameMetadata metadata;
   metadata.root_scroll_offset =
       gfx::ScrollOffsetToVector2dF(active_tree_->TotalScrollOffset());
@@ -1934,6 +1935,8 @@ RenderFrameMetadata LayerTreeHostImpl::MakeRenderFrameMetadata() {
     metadata.root_overflow_y_hidden |=
         !inner_viewport_scroll_node->user_scrollable_vertical;
   }
+  metadata.has_transparent_background =
+      frame->render_passes.back()->has_transparent_background;
 
   metadata.root_background_color = active_tree_->background_color();
   metadata.is_scroll_offset_at_top = active_tree_->TotalScrollOffset().y() == 0;
@@ -2052,7 +2055,7 @@ bool LayerTreeHostImpl::DrawLayers(FrameData* frame) {
   DCHECK_EQ(metadata.frame_token + 1, next_frame_token_);
 
   if (render_frame_metadata_observer_) {
-    last_draw_render_frame_metadata_ = MakeRenderFrameMetadata();
+    last_draw_render_frame_metadata_ = MakeRenderFrameMetadata(frame);
     render_frame_metadata_observer_->OnRenderFrameSubmission(
         *last_draw_render_frame_metadata_, &metadata);
   }

cc/trees/layer_tree_host_impl.h

@@ -623,7 +623,7 @@ class CC_EXPORT LayerTreeHostImpl
   void ScheduleMicroBenchmark(std::unique_ptr<MicroBenchmarkImpl> benchmark);
 
   viz::CompositorFrameMetadata MakeCompositorFrameMetadata();
-  RenderFrameMetadata MakeRenderFrameMetadata();
+  RenderFrameMetadata MakeRenderFrameMetadata(FrameData* frame);
 
   // Viewport rectangle and clip in device space.  These rects are used to
   // prioritize raster and determine what is submitted in a CompositorFrame.

cc/trees/render_frame_metadata.cc

@@ -32,6 +32,7 @@ bool RenderFrameMetadata::HasAlwaysUpdateMetadataChanged(
          rfm1.root_overflow_y_hidden != rfm2.root_overflow_y_hidden ||
          rfm1.scrollable_viewport_size != rfm2.scrollable_viewport_size ||
          rfm1.root_layer_size != rfm2.root_layer_size ||
+         rfm1.has_transparent_background != rfm2.has_transparent_background ||
 #endif
          rfm1.is_mobile_optimized != rfm2.is_mobile_optimized ||
          rfm1.device_scale_factor != rfm2.device_scale_factor ||
@@ -60,6 +61,7 @@ bool RenderFrameMetadata::operator==(const RenderFrameMetadata& other) const {
          root_overflow_y_hidden == other.root_overflow_y_hidden &&
          scrollable_viewport_size == other.scrollable_viewport_size &&
          root_layer_size == other.root_layer_size &&
+         has_transparent_background == other.has_transparent_background &&
          is_mobile_optimized == other.is_mobile_optimized &&
          device_scale_factor == other.device_scale_factor &&
          viewport_size_in_pixels == other.viewport_size_in_pixels &&

cc/trees/render_frame_metadata.h

@@ -39,6 +39,10 @@ class CC_EXPORT RenderFrameMetadata {
   // whether scroll_offset.y() == 0.
   bool is_scroll_offset_at_top = true;
 
+  // Returns whether the root RenderPass of the CompositorFrame has a
+  // transparent background color.
+  bool has_transparent_background = false;
+
   // 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.

content/browser/renderer_host/render_widget_host_view_android.cc

@@ -1233,7 +1233,6 @@ void RenderWidgetHostViewAndroid::OnFrameMetadataUpdated(
       root_layer_size_dip, scrollable_viewport_size_dip, top_content_offset_dip,
       top_shown_pix, controls_changed);
 
-  // TODO(fsamuel): Plumb the |is_transparent| flag through RenderFrameMetadata.
   SetContentBackgroundColor(is_transparent ? SK_ColorTRANSPARENT
                                            : metadata.root_background_color);
 
@@ -1386,6 +1385,10 @@ void RenderWidgetHostViewAndroid::OnDidUpdateVisualPropertiesComplete(
       metadata.top_controls_shown_ratio, metadata.bottom_controls_height,
       metadata.bottom_controls_shown_ratio);
 
+  SetContentBackgroundColor(metadata.has_transparent_background
+                                ? SK_ColorTRANSPARENT
+                                : metadata.root_background_color);
+
   // All offsets and sizes except |top_shown_pix| are in CSS pixels.
   gesture_listener_manager_->UpdateScrollInfo(
       root_scroll_offset_dip, metadata.page_scale_factor,

content/common/render_frame_metadata.mojom

@@ -36,6 +36,9 @@ struct RenderFrameMetadata {
   gfx.mojom.SizeF scrollable_viewport_size;
   gfx.mojom.SizeF root_layer_size;
 
+  [EnableIf=is_android]
+  bool has_transparent_background;
+
   // 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.

content/common/render_frame_metadata_struct_traits.cc

@@ -4,6 +4,7 @@
 
 #include "content/common/render_frame_metadata_struct_traits.h"
 
+#include "build/build_config.h"
 #include "services/viz/public/cpp/compositing/selection_struct_traits.h"
 #include "ui/gfx/geometry/mojo/geometry_struct_traits.h"
 #include "ui/gfx/mojo/selection_bound_struct_traits.h"
@@ -27,6 +28,9 @@ bool StructTraits<content::mojom::RenderFrameMetadataDataView,
   out->top_controls_shown_ratio = data.top_controls_shown_ratio();
   out->bottom_controls_height = data.bottom_controls_height();
   out->bottom_controls_shown_ratio = data.bottom_controls_shown_ratio();
+#if defined(OS_ANDROID)
+  out->has_transparent_background = data.has_transparent_background();
+#endif
   return data.ReadRootScrollOffset(&out->root_scroll_offset) &&
          data.ReadSelection(&out->selection) &&
          data.ReadScrollableViewportSize(&out->scrollable_viewport_size) &&

content/common/render_frame_metadata_struct_traits.h

@@ -60,6 +60,11 @@ struct StructTraits<content::mojom::RenderFrameMetadataDataView,
     return metadata.root_layer_size;
   }
 
+  static bool has_transparent_background(
+      const cc::RenderFrameMetadata& metadata) {
+    return metadata.has_transparent_background;
+  }
+
   static bool is_mobile_optimized(const cc::RenderFrameMetadata& metadata) {
     return metadata.is_mobile_optimized;
   }