WIP: Surface Synchronization System

cc/layers/surface_layer_impl.cc

Index: cc/layers/surface_layer_impl.cc
diff --git a/cc/layers/surface_layer_impl.cc b/cc/layers/surface_layer_impl.cc
index e23e789c4096276c97274f64399be9e3d91d9b13..f24ff175c2d149da1adb06ee66c53271ab72054d 100644
--- a/cc/layers/surface_layer_impl.cc
+++ b/cc/layers/surface_layer_impl.cc
@@ -29,11 +29,19 @@ std::unique_ptr<LayerImpl> SurfaceLayerImpl::CreateLayerImpl(
   return SurfaceLayerImpl::Create(tree_impl, id());
 }
 
-void SurfaceLayerImpl::SetSurfaceInfo(const SurfaceInfo& surface_info) {
-  if (surface_info_ == surface_info)
+void SurfaceLayerImpl::SetPrimarySurfaceInfo(const SurfaceInfo& surface_info) {
+  if (primary_surface_info_ == surface_info)
     return;
 
-  surface_info_ = surface_info;
+  primary_surface_info_ = surface_info;
+  NoteLayerPropertyChanged();
+}
+
+void SurfaceLayerImpl::SetFallbackSurfaceInfo(const SurfaceInfo& surface_info) {
+  if (fallback_surface_info_ == surface_info)
+    return;
+
+  fallback_surface_info_ = surface_info;
   NoteLayerPropertyChanged();
 }
 
@@ -48,12 +56,38 @@ void SurfaceLayerImpl::SetStretchContentToFillBounds(bool stretch_content) {
 void SurfaceLayerImpl::PushPropertiesTo(LayerImpl* layer) {
   LayerImpl::PushPropertiesTo(layer);
   SurfaceLayerImpl* layer_impl = static_cast<SurfaceLayerImpl*>(layer);
-  layer_impl->SetSurfaceInfo(surface_info_);
+  layer_impl->SetPrimarySurfaceInfo(primary_surface_info_);
+  layer_impl->SetFallbackSurfaceInfo(fallback_surface_info_);
   layer_impl->SetStretchContentToFillBounds(stretch_content_to_fill_bounds_);
 }
 
 void SurfaceLayerImpl::AppendQuads(RenderPass* render_pass,
                                    AppendQuadsData* append_quads_data) {
+  SurfaceDrawQuad* primary_draw_quad =
+      render_pass->CreateAndAppendDrawQuad<SurfaceDrawQuad>();
+  SurfaceDrawQuad* fallback_draw_quad = nullptr;
+  if (fallback_surface_info_.id().is_valid()) {
+    fallback_draw_quad =
+        render_pass->CreateAndAppendDrawQuad<SurfaceDrawQuad>();
+  }
+  PopulateSurfaceDrawQuad(render_pass, primary_draw_quad, fallback_draw_quad,
+                          SurfaceDrawQuadType::PRIMARY, primary_surface_info_);
+  if (fallback_draw_quad) {
+    PopulateSurfaceDrawQuad(render_pass, fallback_draw_quad, nullptr,
+                            SurfaceDrawQuadType::FALLBACK,
+                            fallback_surface_info_);
+  }
+}
+
+void SurfaceLayerImpl::PopulateSurfaceDrawQuad(
+    RenderPass* render_pass,
+    SurfaceDrawQuad* surface_draw_quad,
+    SurfaceDrawQuad* fallback_surface_draw_quad,
+    SurfaceDrawQuadType surface_draw_quad_type,
+    const SurfaceInfo& surface_info) {
+  if (!surface_info.id().is_valid())
+    return;
+
   AppendRainbowDebugBorder(render_pass);
 
   SharedQuadState* shared_quad_state =
@@ -62,32 +96,28 @@ void SurfaceLayerImpl::AppendQuads(RenderPass* render_pass,
   if (stretch_content_to_fill_bounds_) {
     // Stretches the surface contents to exactly fill the layer bounds,
     // regardless of scale or aspect ratio differences.
-    float scale_x = static_cast<float>(surface_info_.size_in_pixels().width()) /
+    float scale_x = static_cast<float>(surface_info.size_in_pixels().width()) /
                     bounds().width();
-    float scale_y =
-        static_cast<float>(surface_info_.size_in_pixels().height()) /
-        bounds().height();
+    float scale_y = static_cast<float>(surface_info.size_in_pixels().height()) /
+                    bounds().height();
     PopulateScaledSharedQuadState(shared_quad_state, scale_x, scale_y);
   } else {
     PopulateScaledSharedQuadState(shared_quad_state,
-                                  surface_info_.device_scale_factor(),
-                                  surface_info_.device_scale_factor());
+                                  surface_info.device_scale_factor(),
+                                  surface_info.device_scale_factor());
   }
 
-  if (!surface_info_.id().is_valid())
-    return;
-
-  gfx::Rect quad_rect(surface_info_.size_in_pixels());
+  gfx::Rect quad_rect(surface_info.size_in_pixels());
   gfx::Rect visible_quad_rect =
       draw_properties().occlusion_in_content_space.GetUnoccludedContentRect(
           quad_rect);
 
   if (visible_quad_rect.IsEmpty())
     return;
-  SurfaceDrawQuad* quad =
-      render_pass->CreateAndAppendDrawQuad<SurfaceDrawQuad>();
-  quad->SetNew(shared_quad_state, quad_rect, visible_quad_rect,
-               surface_info_.id());
+
+  surface_draw_quad->SetNew(shared_quad_state, quad_rect, visible_quad_rect,
+                            surface_info.id(), surface_draw_quad_type,
+                            fallback_surface_draw_quad);
 }
 
 void SurfaceLayerImpl::GetDebugBorderProperties(SkColor* color,
@@ -185,7 +215,7 @@ void SurfaceLayerImpl::AppendRainbowDebugBorder(RenderPass* render_pass) {
 
 void SurfaceLayerImpl::AsValueInto(base::trace_event::TracedValue* dict) const {
   LayerImpl::AsValueInto(dict);
-  dict->SetString("surface_id", surface_info_.id().ToString());
+  dict->SetString("surface_id", primary_surface_info_.id().ToString());
 }
 
 const char* SurfaceLayerImpl::LayerTypeAsString() const {