[Command buffer] workaround the framebuffer completeness bug for Intel Mac

gpu/command_buffer/service/framebuffer_manager.h

Index: gpu/command_buffer/service/framebuffer_manager.h
diff --git a/gpu/command_buffer/service/framebuffer_manager.h b/gpu/command_buffer/service/framebuffer_manager.h
index eab5809d63145562acb0564d46d59c61a454ad40..cfbb9b86ea11c3a2c68443f105b57b13beb98e9c 100644
--- a/gpu/command_buffer/service/framebuffer_manager.h
+++ b/gpu/command_buffer/service/framebuffer_manager.h
@@ -147,6 +147,10 @@ class GPU_EXPORT Framebuffer : public base::RefCounted<Framebuffer> {
     return has_been_bound_ && !IsDeleted();
   }
 
+  bool ReadBufferHasNoImage() const;
+  bool DrawBuffersHaveMissingImage(GLsizei* num, GLenum* buf) const;
+  bool ColorBuffersHaveImage() const;
+
   bool HasColorAttachment(int index) const;
   bool HasDepthAttachment() const;
   bool HasStencilAttachment() const;