Complete disable_gl_rgb_format workaround for Mali-400 GPU

gpu/command_buffer/service/framebuffer_manager.cc

Index: gpu/command_buffer/service/framebuffer_manager.cc
diff --git a/gpu/command_buffer/service/framebuffer_manager.cc b/gpu/command_buffer/service/framebuffer_manager.cc
index 0b42bf5e267ce3045d4200c0fd2c468e5a4ca0a2..7b7b480d7663893a941596e19a5dcdfbb89c3180 100644
--- a/gpu/command_buffer/service/framebuffer_manager.cc
+++ b/gpu/command_buffer/service/framebuffer_manager.cc
@@ -472,6 +472,15 @@ bool Framebuffer::HasStencilAttachment() const {
          attachments_.find(GL_STENCIL_ATTACHMENT) != attachments_.end();
 }
 
+GLenum Framebuffer::GetColorAttachment0Format() const {
+  AttachmentMap::const_iterator it = attachments_.find(GL_COLOR_ATTACHMENT0);
+  if (it == attachments_.end()) {
+    return 0;
+  }
+  const Attachment* attachment = it->second.get();
+  return attachment->internal_format();
+}
+
 GLenum Framebuffer::GetReadBufferInternalFormat() const {
   if (read_buffer_ == GL_NONE)
     return 0;