Blend TextureLayer background-color at draw time.

cc/layers/texture_layer.cc

Index: cc/layers/texture_layer.cc
diff --git a/cc/layers/texture_layer.cc b/cc/layers/texture_layer.cc
index f2900e6b6f63c77b014fd19e4a3eab29dc5cb460..5a1a45877d042d969cbc03157bbf69e1c7f279b2 100644
--- a/cc/layers/texture_layer.cc
+++ b/cc/layers/texture_layer.cc
@@ -31,6 +31,7 @@ TextureLayer::TextureLayer(TextureLayerClient* client, bool uses_mailbox)
       uv_top_left_(0.f, 0.f),
       uv_bottom_right_(1.f, 1.f),
       premultiplied_alpha_(true),
+      blend_background_color_(false),
       rate_limit_context_(false),
       content_committed_(false),
       texture_id_(0),
@@ -105,6 +106,13 @@ void TextureLayer::SetPremultipliedAlpha(bool premultiplied_alpha) {
   SetNeedsCommit();
 }
 
+void TextureLayer::SetBlendBackgroundColor(bool blend) {
+  if (blend_background_color_ == blend)
+    return;
+  blend_background_color_ = blend;
+  SetNeedsCommit();
+}
+
 void TextureLayer::SetRateLimitContext(bool rate_limit) {
   if (!rate_limit && rate_limit_context_ && client_ && layer_tree_host())
     layer_tree_host()->StopRateLimiter(client_->Context3d());
@@ -202,6 +210,7 @@ void TextureLayer::PushPropertiesTo(LayerImpl* layer) {
   texture_layer->set_uv_bottom_right(uv_bottom_right_);
   texture_layer->set_vertex_opacity(vertex_opacity_);
   texture_layer->set_premultiplied_alpha(premultiplied_alpha_);
+  texture_layer->set_blend_background_color(blend_background_color_);
   if (uses_mailbox_ && needs_set_mailbox_) {
     TextureMailbox texture_mailbox;
     if (holder_ref_) {