cap the number of tabs in the backing store cache

chrome/browser/memory_details.cc

 // Copyright (c) 2006-2008 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 "chrome/browser/memory_details.h"
 #include <psapi.h>
 
 #include "app/l10n_util.h"
 #include "base/file_version_info.h"
 #include "base/string_util.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_thread.h"
+#include "chrome/browser/renderer_host/backing_store_manager.h"
 #include "chrome/browser/renderer_host/render_process_host.h"
 #include "chrome/browser/tab_contents/navigation_entry.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/child_process_host.h"
 #include "chrome/common/url_constants.h"
 #include "grit/chromium_strings.h"
 
 class RenderViewHostDelegate;
 
 // Template of static data we use for finding browser process information.
@@ skipping 246 matching lines @@
     }
   }
 
   UpdateHistograms();
 
   OnDetailsAvailable();
 }
 
 void MemoryDetails::UpdateHistograms() {
   // Reports a set of memory metrics to UMA.
-  // Memory is measured in units of 10KB.
+  // Memory is measured in KB.
 
   ProcessData browser = process_data_[CHROME_BROWSER];
   size_t aggregate_memory = 0;
   int plugin_count = 0;
   int worker_count = 0;
   for (size_t index = 0; index < browser.processes.size(); index++) {
     int sample = static_cast<int>(browser.processes[index].working_set.priv);
     aggregate_memory += sample;
     switch (browser.processes[index].type) {
      case ChildProcessInfo::BROWSER_PROCESS:
        UMA_HISTOGRAM_MEMORY_KB("Memory.Browser", sample);
        break;
      case ChildProcessInfo::RENDER_PROCESS:
        UMA_HISTOGRAM_MEMORY_KB("Memory.Renderer", sample);
        break;
      case ChildProcessInfo::PLUGIN_PROCESS:
        UMA_HISTOGRAM_MEMORY_KB("Memory.Plugin", sample);
        plugin_count++;
        break;
      case ChildProcessInfo::WORKER_PROCESS:
        UMA_HISTOGRAM_MEMORY_KB("Memory.Worker", sample);
        worker_count++;
        break;
     }
   }
+  UMA_HISTOGRAM_MEMORY_KB("Memory.BackingStore",
+                          BackingStoreManager::MemorySize() / 1024);
 
   UMA_HISTOGRAM_COUNTS_100("Memory.ProcessCount",
       static_cast<int>(browser.processes.size()));
   UMA_HISTOGRAM_COUNTS_100("Memory.PluginProcessCount", plugin_count);
   UMA_HISTOGRAM_COUNTS_100("Memory.WorkerProcessCount", worker_count);
 
   int total_sample = static_cast<int>(aggregate_memory / 1000);
   UMA_HISTOGRAM_MEMORY_MB("Memory.Total", total_sample);
 }