Make DrawingBuffer and Canvas2DLayerBridge be cc::TextureLayerClients.

third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp

Index: third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
diff --git a/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp b/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
index 5fbbbae804cc29c5758b026e8aa9762a0231e295..a376b6c1e45025880a6e39a082736ecacc529a4a 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
+++ b/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
@@ -646,20 +646,7 @@ ImageBitmap* WebGLRenderingContextBase::transferToImageBitmapBase()
 {
     if (!drawingBuffer())
         return nullptr;
-    WebExternalTextureMailbox mailbox;
-    drawingBuffer()->prepareMailbox(&mailbox, 0);
-    ImageBitmap* imageBitmap;
-    // If the mailbox is invalid, return an transparent black ImageBitmap.
-    // The only situation this could happen is when two or more calls to transferToImageBitmap are made back-to-back.
-    if (mailbox.textureSize.width == 0 && mailbox.textureSize.height == 0) {
-        sk_sp<SkSurface>surface = SkSurface::MakeRasterN32Premul(drawingBuffer()->size().width(), drawingBuffer()->size().height());
-        imageBitmap = ImageBitmap::create(StaticBitmapImage::create(fromSkSp(surface->makeImageSnapshot())));
-    } else {
-        imageBitmap = ImageBitmap::create(mailbox);
-    }
-    // TODO(xidachen): Create a small pool of recycled textures from ImageBitmapRenderingContext's
-    // transferFromImageBitmap, and try to use them in DrawingBuffer.
-    return imageBitmap;
+    return ImageBitmap::create(drawingBuffer()->transferToStaticBitmapImage());
 }
 
 namespace {