Fix a bug where an infinite stream of BeginFrame messages are sent to extensions.

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 466 matching lines @@
 
   // Let the page-level input event router know about our surface ID
   // namespace for surface-based hit testing.
   if (render_widget_host_->delegate() &&
       render_widget_host_->delegate()->GetInputEventRouter()) {
     render_widget_host_->delegate()->GetInputEventRouter()->AddFrameSinkIdOwner(
         GetFrameSinkId(), this);
   }
 
   RenderViewHost* rvh = RenderViewHost::From(render_widget_host_);
+  bool needs_begin_frames = true;
   if (rvh) {

[danakj, 2016/12/15 17:30:10]

Can you add a TODO to remove this condition?

[erikchen, 2016/12/15 19:28:22]

Done.

     // TODO(mostynb): actually use prefs.  Landing this as a separate CL
     // first to rebaseline some unreliable layout tests.
     ignore_result(rvh->GetWebkitPreferences());
+    needs_begin_frames = !rvh->GetDelegate()->IsNeverVisible();
   }
 
   if (GetTextInputManager())
     GetTextInputManager()->AddObserver(this);
 
   // Because of the way Mac pumps messages during resize, (see the code
   // in RenderMessageFilter::OnMessageReceived), SetNeedsBeginFrame
   // messages are not delayed on Mac.  This leads to creation-time
   // raciness where renderer sends a SetNeedsBeginFrame(true) before
-  // the renderer host is created to recieve it.  In general, all
-  // renderers want begin frames initially anyway, so start this value
-  // at true here to avoid startup raciness and decrease latency.
-  needs_begin_frames_ = true;
+  // the renderer host is created to recieve it.
+  //

[danakj, 2016/12/15 17:30:10]

nit: just one line between paragraphs

[erikchen, 2016/12/15 19:28:22]

Done.

+  //
+  // Any renderer that will produce frames needs to have begin frames sent to
+  // it. So unless it is never visible, start this value at true here to avoid
+  // startup raciness and decrease latency.
+  needs_begin_frames_ = needs_begin_frames;
   UpdateNeedsBeginFramesInternal();
 }
 
 RenderWidgetHostViewMac::~RenderWidgetHostViewMac() {
   display::Screen::GetScreen()->RemoveObserver(this);
 
   // This is being called from |cocoa_view_|'s destructor, so invalidate the
   // pointer.
   cocoa_view_ = nil;
 
@@ skipping 2929 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