Blend TextureLayer background-color at draw time.

cc/layers/texture_layer_impl.cc

Index: cc/layers/texture_layer_impl.cc
diff --git a/cc/layers/texture_layer_impl.cc b/cc/layers/texture_layer_impl.cc
index c5258cf91f48a6c1285c68478add84961f5f54d3..a9d6158fd83bb642a7d70b28e3f4a34becfded71 100644
--- a/cc/layers/texture_layer_impl.cc
+++ b/cc/layers/texture_layer_impl.cc
@@ -19,6 +19,7 @@ TextureLayerImpl::TextureLayerImpl(LayerTreeImpl* tree_impl,
       texture_id_(0),
       external_texture_resource_(0),
       premultiplied_alpha_(true),
+      blend_background_color_(false),
       flipped_(true),
       uv_top_left_(0.f, 0.f),
       uv_bottom_right_(1.f, 1.f),
@@ -86,8 +87,11 @@ void TextureLayerImpl::AppendQuads(QuadSink* quad_sink,
       quad_sink->UseSharedQuadState(CreateSharedQuadState());
   AppendDebugBorderQuad(quad_sink, shared_quad_state, append_quads_data);
 
+  SkColor bg_color = blend_background_color_ ?
+      background_color() : SK_ColorTRANSPARENT;

[alokp, 2013/07/02 22:36:05]

TextureDrawQuad::background_color is always 0 unless
TextureLayer::blend_background_color is set.

   gfx::Rect quad_rect(content_bounds());
-  gfx::Rect opaque_rect(contents_opaque() ? quad_rect : gfx::Rect());
+  gfx::Rect opaque_rect = contents_opaque() || (SkColorGetA(bg_color) == 0xFF) ?
+      quad_rect : gfx::Rect();
   scoped_ptr<TextureDrawQuad> quad = TextureDrawQuad::Create();
   quad->SetNew(shared_quad_state,
                quad_rect,
@@ -97,6 +101,7 @@ void TextureLayerImpl::AppendQuads(QuadSink* quad_sink,
                uv_top_left_,
                uv_bottom_right_,
                vertex_opacity_,
+               bg_color,
                flipped_);
 
   // Perform explicit clipping on a quad to avoid setting a scissor later.