glBindTexImage2DCHROMIUM should retain pixel format.

gpu/command_buffer/service/texture_definition.cc

Index: gpu/command_buffer/service/texture_definition.cc
diff --git a/gpu/command_buffer/service/texture_definition.cc b/gpu/command_buffer/service/texture_definition.cc
index d81d2583b39b650f5c27b97d41b034d26e0cd73c..ab720b1438368d205e87ef76f805d98589806653 100644
--- a/gpu/command_buffer/service/texture_definition.cc
+++ b/gpu/command_buffer/service/texture_definition.cc
@@ -31,6 +31,7 @@ class GLImageSync : public gfx::GLImage {
   // Implement GLImage.
   void Destroy(bool have_context) override;
   gfx::Size GetSize() override;
+  unsigned GetInternalFormat() override;
   bool BindTexImage(unsigned target) override;
   void ReleaseTexImage(unsigned target) override;
   bool CopyTexImage(unsigned target) override;
@@ -73,6 +74,10 @@ gfx::Size GLImageSync::GetSize() {
   return size_;
 }
 
+unsigned GLImageSync::GetInternalFormat() {
+  return GL_RGBA;
+}
+
 bool GLImageSync::BindTexImage(unsigned target) {
   NOTREACHED();
   return false;