Implement native GMB backbuffers in the GLES2 Command Decoder.

cc/test/test_image_factory.cc

Index: cc/test/test_image_factory.cc
diff --git a/cc/test/test_image_factory.cc b/cc/test/test_image_factory.cc
index e9a09bee452474db1e01dfadd002321f7fbf5fbd..ceea8fcb22421ab657cd7d3db9e60c68367d2eed 100644
--- a/cc/test/test_image_factory.cc
+++ b/cc/test/test_image_factory.cc
@@ -34,4 +34,12 @@ scoped_refptr<gl::GLImage> TestImageFactory::CreateImageForGpuMemoryBuffer(
   return image;
 }
 
+scoped_refptr<gl::GLImage> TestImageFactory::CreateAnonymousImage(
+    const gfx::Size& size,
+    gfx::BufferFormat format,
+    unsigned internalformat) {
+  NOTIMPLEMENTED();
+  return nullptr;
+}
+
 }  // namespace cc