Add command buffer support for GL_RGB CHROMIUM image emulation.

ui/gl/gl_image_io_surface.h

Index: ui/gl/gl_image_io_surface.h
diff --git a/ui/gl/gl_image_io_surface.h b/ui/gl/gl_image_io_surface.h
index d8b731828f26d674176401f38b89489857fed367..62b616459f226a931a7ee51ba84cf57ec7d49e43 100644
--- a/ui/gl/gl_image_io_surface.h
+++ b/ui/gl/gl_image_io_surface.h
@@ -49,6 +49,7 @@ class GL_EXPORT GLImageIOSurface : public GLImage {
   void OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd,
                     uint64_t process_tracing_id,
                     const std::string& dump_name) override;
+  bool EmulatingRGB() const override;
 
   gfx::GenericSharedMemoryId io_surface_id() const { return io_surface_id_; }
   base::ScopedCFTypeRef<IOSurfaceRef> io_surface();
@@ -62,7 +63,14 @@ class GL_EXPORT GLImageIOSurface : public GLImage {
 
  private:
   const gfx::Size size_;
+
+  // The "internalformat" exposed to the command buffer, which may not be
+  // "internalformat" requested by the client.
   const unsigned internalformat_;
+
+  // The "internalformat" requested by the client.
+  const unsigned client_internalformat_;
+
   gfx::BufferFormat format_;
   base::ScopedCFTypeRef<IOSurfaceRef> io_surface_;
   gfx::GenericSharedMemoryId io_surface_id_;