Getting rid of DelegatedFrameData

content/browser/renderer_host/render_widget_host_view_mac.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #import <Carbon/Carbon.h>
 #import <objc/runtime.h>
 #include <OpenGL/gl.h>
 #include <QuartzCore/QuartzCore.h>
@@ skipping 1389 matching lines @@
 
 void RenderWidgetHostViewMac::OnSwapCompositorFrame(
     uint32_t compositor_frame_sink_id,
     cc::CompositorFrame frame) {
   TRACE_EVENT0("browser", "RenderWidgetHostViewMac::OnSwapCompositorFrame");
 
   last_scroll_offset_ = frame.metadata.root_scroll_offset;
 
   page_at_minimum_scale_ =
       frame.metadata.page_scale_factor == frame.metadata.min_page_scale_factor;
-  if (frame.delegated_frame_data) {
-    browser_compositor_->SwapCompositorFrame(compositor_frame_sink_id,
-                                             std::move(frame));
-    UpdateDisplayVSyncParameters();
-  } else {
-    DLOG(ERROR) << "Received unexpected frame type.";
-    bad_message::ReceivedBadMessage(render_widget_host_->GetProcess(),
-                                    bad_message::RWHVM_UNEXPECTED_FRAME_TYPE);

[boliu, 2016/10/25 23:00:30]

you can mark this enum as unused in bad_message.h, also you can stop including
bad_message.h here

-  }
+  browser_compositor_->SwapCompositorFrame(compositor_frame_sink_id,
+                                           std::move(frame));
+  UpdateDisplayVSyncParameters();
 }
 
 void RenderWidgetHostViewMac::ClearCompositorFrame() {
   browser_compositor_->GetDelegatedFrameHost()->ClearDelegatedFrame();
 }
 
 gfx::Rect RenderWidgetHostViewMac::GetBoundsInRootWindow() {
   // TODO(shess): In case of !window, the view has been removed from
   // the view hierarchy because the tab isn't main.  Could retrieve
   // the information from the main tab for our window.
@@ skipping 1983 matching lines @@
 
 // "-webkit-app-region: drag | no-drag" is implemented on Mac by excluding
 // regions that are not draggable. (See ControlRegionView in
 // native_app_window_cocoa.mm). This requires the render host view to be
 // draggable by default.
 - (BOOL)mouseDownCanMoveWindow {
   return YES;
 }
 
 @end