Show that ResizeLock is racey with renderer frames in flight.

content/browser/renderer_host/delegated_frame_host.cc

 // Copyright 2014 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/delegated_frame_host.h"
 
 #include <algorithm>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 74 matching lines @@
 
 void DelegatedFrameHost::MaybeCreateResizeLock() {
   if (!ShouldCreateResizeLock())
     return;
   DCHECK(compositor_);
 
   bool defer_compositor_lock =
       can_lock_compositor_ == NO_PENDING_RENDERER_FRAME ||
       can_lock_compositor_ == NO_PENDING_COMMIT;
 
-  if (can_lock_compositor_ == YES_CAN_LOCK)
-    can_lock_compositor_ = YES_DID_LOCK;
-
   resize_lock_ = client_->DelegatedFrameHostCreateResizeLock();
   if (!defer_compositor_lock) {
     bool locked = resize_lock_->Lock();
     DCHECK(locked);
+    can_lock_compositor_ = YES_DID_LOCK;
   }
 }
 
 bool DelegatedFrameHost::ShouldCreateResizeLock() {
   static const bool is_disabled =
       base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kDisableResizeLock);
   if (is_disabled)
     return false;
 
@@ skipping 763 matching lines @@
   }
 
   if (!skipped_frames_) {
     latest_confirmed_begin_frame_source_id_ = ack.source_id;
     latest_confirmed_begin_frame_sequence_number_ =
         ack.latest_confirmed_sequence_number;
   }
 }
 
 }  // namespace content