Fix memory leaks from adding GPU memory to task manager

chrome/browser/task_manager/task_manager.h

 // 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.
 
 #ifndef CHROME_BROWSER_TASK_MANAGER_TASK_MANAGER_H_
 #define CHROME_BROWSER_TASK_MANAGER_TASK_MANAGER_H_
 
 #include <map>
 #include <utility>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/singleton.h"
 #include "base/observer_list.h"
 #include "base/process_util.h"
 #include "base/string16.h"
 #include "base/timer.h"
 #include "chrome/browser/renderer_host/web_cache_manager.h"
 #include "content/public/common/gpu_memory_stats.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebCache.h"
 
 class TaskManagerModel;
+class TaskManagerModelGpuDataManagerObserver;
 
 namespace base {
 class ProcessMetrics;
 }
 
 namespace content {
 class WebContents;
 }
 
 namespace extensions {
@@ skipping 529 matching lines @@
   // per second. It is computed every time the timer ticks. The Resources are
   // owned by the ResourceProviders.
   ResourceValueMap displayed_network_usage_map_;
 
   // A map that contains the CPU usage (in %) for a process since last refresh.
   CPUUsageMap cpu_usage_map_;
 
   // A map that contains the video memory usage for a process
   content::GPUVideoMemoryUsageStats video_memory_usage_stats_;
   bool pending_video_memory_usage_stats_update_;
 

[ccameron, 2012/08/20 21:20:02]

The dtor for the observer will call into GpuDataManagerImpl::RemoveObserver --
do we have guarantees of dtor order here?

+  // An observer waiting for video memory usage stats updates from the GPU
+  // process
+  scoped_ptr<TaskManagerModelGpuDataManagerObserver>
+      video_memory_usage_stats_observer_;
+
   // A map that contains the private/shared memory usage of the process. We
   // cache this because the same APIs are called on linux and windows, and
   // because the linux call takes >10ms to complete. This cache is cleared on
   // every Refresh().
   mutable MemoryUsageMap memory_usage_map_;
 
   ObserverList<TaskManagerModelObserver> observer_list_;
 
   // How many calls to StartUpdating have been made without matching calls to
   // StopUpdating.
   int update_requests_;
 
   // How many calls to StartListening have been made without matching calls to
   // StopListening.
   int listen_requests_;
 
   // Whether we are currently in the process of updating.
   UpdateState update_state_;
 
   // A salt lick for the goats.
   uint64 goat_salt_;
 
   // Resource identifier that is unique within single session.
   int last_unique_id_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskManagerModel);
 };
 
 #endif  // CHROME_BROWSER_TASK_MANAGER_TASK_MANAGER_H_