[tracing] Add WebCache memory usage in Blink to chrome://tracing

components/web_cache/browser/web_cache_manager.h

 // Copyright (c) 2011 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.
 
 // This is the browser side of the cache manager, it tracks the activity of the
 // render processes and allocates available memory cache resources.
 
 #ifndef COMPONENTS_WEB_CACHE_BROWSER_WEB_CACHE_MANAGER_H_
 #define COMPONENTS_WEB_CACHE_BROWSER_WEB_CACHE_MANAGER_H_
 
 #include <list>
 #include <map>
 #include <set>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
+#include "base/trace_event/memory_dump_provider.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "third_party/WebKit/public/web/WebCache.h"
 
 template<typename Type>
 struct DefaultSingletonTraits;
 class PrefRegistrySimple;
 
 namespace web_cache {
 
-class WebCacheManager : public content::NotificationObserver {
+class WebCacheManager : public content::NotificationObserver,
+                        public base::trace_event::MemoryDumpProvider {
   friend class WebCacheManagerTest;
   FRIEND_TEST_ALL_PREFIXES(
       WebCacheManagerTest,
       CallRemoveRendererAndObserveActivityInAnyOrderShouldNotCrashTest_1);
   FRIEND_TEST_ALL_PREFIXES(
       WebCacheManagerTest,
       CallRemoveRendererAndObserveActivityInAnyOrderShouldNotCrashTest_2);
   FRIEND_TEST_ALL_PREFIXES(
       WebCacheManagerTest,
       CallRemoveRendererAndObserveActivityInAnyOrderShouldNotCrashTest_3);
@@ skipping 50 matching lines @@
 
   // Clears all in-memory caches when a tab is reloaded or the user navigates
   // to a different website.
   void ClearCacheOnNavigation();
 
   // content::NotificationObserver implementation:
   void Observe(int type,
                const content::NotificationSource& source,
                const content::NotificationDetails& details) override;
 
+  // base::trace_event::MemoryDUmpProvider implementation.
+  bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
+                    base::trace_event::ProcessMemoryDump* pmd) override;
+
   // Gets the default global size limit.  This interrogates system metrics to
   // tune the default size to the current system.
   static size_t GetDefaultGlobalSizeLimit();
 
  protected:
   // The amount of idle time before we consider a tab to be "inactive"
   static const int kRendererInactiveThresholdMinutes = 5;
 
   // Keep track of some renderer information.
   struct RendererInfo : blink::WebCache::UsageStats {
@@ skipping 99 matching lines @@
     ON_NAVIGATION
   };
 
   // Inform all |renderers| to clear their cache.
   void ClearRendererCache(const std::set<int>& renderers,
                           ClearCacheOccasion occation);
 
   // Check to see if any active renderers have fallen inactive.
   void FindInactiveRenderers();
 
+  // Helper method to dump the cache usage stats of given renderer.
+  void DumpUsageStats(int renderer_id,

[Primiano Tucci (use gerrit), 2015/08/12 10:04:45]

nit: how about DumpMemoryStatsForRenderer ?

+                      base::trace_event::ProcessMemoryDump* pmd);
+
   // The global size limit for all in-memory caches.
   size_t global_size_limit_;
 
   // Maps every renderer_id our most recent copy of its statistics.
   StatsMap stats_;
 
   // Every renderer we think is still around is in one of these two sets.
   //
   // Active renderers are those renderers that have been active more recently
   // than they have been inactive.
   std::set<int> active_renderers_;
   // Inactive renderers are those renderers that have been inactive more
   // recently than they have been active.
   std::set<int> inactive_renderers_;
 
   content::NotificationRegistrar registrar_;
 
   base::WeakPtrFactory<WebCacheManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebCacheManager);
 };
 
 }  // namespace web_cache
 
 #endif  // COMPONENTS_WEB_CACHE_BROWSER_WEB_CACHE_MANAGER_H_