Consider background-color opacity for TextureLayer opaque region.

TextureLayer draws both - texture and background-color.
So take background-color opacity into account when calculating
opaque region.

BUG=236982

Review URL: https://chromiumcodereview.appspot.com/21084005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@214682 0039d316-1c4b-4281-b951-d872f2087c98

cc/layers/texture_layer.cc

@@ -232,6 +232,16 @@ void TextureLayer::PushPropertiesTo(LayerImpl* layer) {
   content_committed_ = DrawsContent();
 }
 
+Region TextureLayer::VisibleContentOpaqueRegion() const {
+  if (contents_opaque())
+    return visible_content_rect();
+
+  if (blend_background_color_ && (SkColorGetA(background_color()) == 0xFF))
+    return visible_content_rect();
+
+  return Region();
+}
+
 bool TextureLayer::BlocksPendingCommit() const {
   // Double-buffered texture layers need to be blocked until they can be made
   // triple-buffered.  Single-buffered layers already prevent draws, so

cc/layers/texture_layer.h

@@ -82,6 +82,7 @@ class CC_EXPORT TextureLayer : public Layer {
   virtual bool Update(ResourceUpdateQueue* queue,
                       const OcclusionTracker* occlusion) OVERRIDE;
   virtual void PushPropertiesTo(LayerImpl* layer) OVERRIDE;
+  virtual Region VisibleContentOpaqueRegion() const OVERRIDE;
   virtual bool BlocksPendingCommit() const OVERRIDE;
 
   virtual bool CanClipSelf() const OVERRIDE;

cc/layers/texture_layer_impl.cc

@@ -194,6 +194,16 @@ void TextureLayerImpl::DidDraw(ResourceProvider* resource_provider) {
   external_texture_resource_ = 0;
 }
 
+Region TextureLayerImpl::VisibleContentOpaqueRegion() const {
+  if (contents_opaque())
+    return visible_content_rect();
+
+  if (blend_background_color_ && (SkColorGetA(background_color()) == 0xFF))
+    return visible_content_rect();
+
+  return Region();
+}
+
 void TextureLayerImpl::DidLoseOutputSurface() {
   if (external_texture_resource_ && !uses_mailbox_) {
     ResourceProvider* resource_provider =

cc/layers/texture_layer_impl.h

@@ -32,7 +32,7 @@ class CC_EXPORT TextureLayerImpl : public LayerImpl {
   virtual void AppendQuads(QuadSink* quad_sink,
                            AppendQuadsData* append_quads_data) OVERRIDE;
   virtual void DidDraw(ResourceProvider* resource_provider) OVERRIDE;
-
+  virtual Region VisibleContentOpaqueRegion() const OVERRIDE;
   virtual void DidLoseOutputSurface() OVERRIDE;
 
   unsigned texture_id() const { return texture_id_; }

cc/layers/texture_layer_unittest.cc

@@ -204,6 +204,33 @@ TEST_F(TextureLayerTest, CheckPropertyChangeCausesCorrectBehavior) {
   EXPECT_CALL(*layer_tree_host_, AcquireLayerTextures()).Times(AnyNumber());
 }
 
+TEST_F(TextureLayerTest, VisibleContentOpaqueRegion) {
+  const gfx::Size layer_bounds(100, 100);
+  const gfx::Rect layer_rect(layer_bounds);
+  const Region layer_region(layer_rect);
+
+  scoped_refptr<TextureLayer> layer = TextureLayer::Create(NULL);
+  layer->SetBounds(layer_bounds);
+  layer->draw_properties().visible_content_rect = layer_rect;
+  layer->SetBlendBackgroundColor(true);
+
+  // Verify initial conditions.
+  EXPECT_FALSE(layer->contents_opaque());
+  EXPECT_EQ(0u, layer->background_color());
+  EXPECT_EQ(Region().ToString(),
+            layer->VisibleContentOpaqueRegion().ToString());
+
+  // Opaque background.
+  layer->SetBackgroundColor(SK_ColorWHITE);
+  EXPECT_EQ(layer_region.ToString(),
+            layer->VisibleContentOpaqueRegion().ToString());
+
+  // Transparent background.
+  layer->SetBackgroundColor(SkColorSetARGB(100, 255, 255, 255));
+  EXPECT_EQ(Region().ToString(),
+            layer->VisibleContentOpaqueRegion().ToString());
+}
+
 class FakeTextureLayerClient : public TextureLayerClient {
  public:
   FakeTextureLayerClient() : context_(TestWebGraphicsContext3D::Create()) {}