Expose locks for CopyFromCompositingSurface/CopyFromBackingStore API

content/browser/renderer_host/renderer_frame_manager.cc

 // Copyright 2013 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/renderer_frame_manager.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "base/sys_info.h"
 
 namespace content {
 
 RendererFrameManager* RendererFrameManager::GetInstance() {
   return Singleton<RendererFrameManager>::get();
 }
 
 void RendererFrameManager::AddFrame(RendererFrameManagerClient* frame,
                                     bool locked) {
   RemoveFrame(frame);
   if (locked)
     locked_frames_[frame] = 1;
   else
     unlocked_frames_.push_front(frame);
   CullUnlockedFrames();
 }
 
 void RendererFrameManager::RemoveFrame(RendererFrameManagerClient* frame) {
-  std::map<RendererFrameManagerClient*, size_t>::iterator locked_iter =
-      locked_frames_.find(frame);
+  LockedFrameCount::iterator locked_iter = locked_frames_.find(frame);
   if (locked_iter != locked_frames_.end())
     locked_frames_.erase(locked_iter);
   unlocked_frames_.remove(frame);
 }
 
 void RendererFrameManager::LockFrame(RendererFrameManagerClient* frame) {
-  std::list<RendererFrameManagerClient*>::iterator unlocked_iter =
+  UnlockedFrames::iterator unlocked_iter =
     std::find(unlocked_frames_.begin(), unlocked_frames_.end(), frame);
   if (unlocked_iter != unlocked_frames_.end()) {
     DCHECK(locked_frames_.find(frame) == locked_frames_.end());
     unlocked_frames_.remove(frame);
     locked_frames_[frame] = 1;
   } else {
     DCHECK(locked_frames_.find(frame) != locked_frames_.end());
     locked_frames_[frame]++;
   }
 }
 
 void RendererFrameManager::UnlockFrame(RendererFrameManagerClient* frame) {
   DCHECK(locked_frames_.find(frame) != locked_frames_.end());
   size_t locked_count = locked_frames_[frame];
   DCHECK(locked_count);
   if (locked_count > 1) {
     locked_frames_[frame]--;
   } else {
     RemoveFrame(frame);
     unlocked_frames_.push_front(frame);
     CullUnlockedFrames();
   }
 }
 
+size_t RendererFrameManager::LockedCount(RendererFrameManagerClient* frame) {
+  LockedFrameCount::iterator iter = locked_frames_.find(frame);
+  if (iter != locked_frames_.end())
+    return iter->second;
+  return 0;
+}
+
 RendererFrameManager::RendererFrameManager() {
   max_number_of_saved_frames_ =
 #if defined(OS_ANDROID)
       1;
 #else
       std::min(5, 2 + (base::SysInfo::AmountOfPhysicalMemoryMB() / 256));
 #endif
 }
 
 RendererFrameManager::~RendererFrameManager() {}
 
 void RendererFrameManager::CullUnlockedFrames() {
   while (!unlocked_frames_.empty() &&
          unlocked_frames_.size() + locked_frames_.size() >
              max_number_of_saved_frames()) {
     size_t old_size = unlocked_frames_.size();
     // Should remove self from list.
     unlocked_frames_.back()->EvictCurrentFrame();
     DCHECK_EQ(unlocked_frames_.size() + 1, old_size);
   }
 }
 
 }  // namespace content