Support saving browser metrics to disk and reading them during next run.

content/browser/browser_main_runner.cc

 // 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.
 
 #include "content/public/browser/browser_main_runner.h"
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/debug/leak_annotations.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/histogram_macros.h"
+#include "base/metrics/persistent_histogram_allocator.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/profiler/scoped_profile.h"
 #include "base/profiler/scoped_tracker.h"
 #include "base/time/time.h"
 #include "base/trace_event/heap_profiler_allocation_context_tracker.h"
 #include "base/trace_event/trace_event.h"
 #include "base/tracked_objects.h"
 #include "build/build_config.h"
 #include "components/tracing/trace_config_file.h"
 #include "components/tracing/tracing_switches.h"
@@ skipping 193 matching lines @@
       // Forcefully terminates the RunLoop inside MessagePumpForUI, ensuring
       // proper shutdown for content_browsertests. Shutdown() is not used by
       // the actual browser.
       if (base::MessageLoop::current()->is_running())
         base::MessageLoop::current()->QuitNow();
   #endif
       main_loop_.reset(NULL);
 
       notification_service_.reset(NULL);
 
+      // Dump all the persistent metrics to a file for upload during the next
+      // run of the browser.
+      base::GlobalHistogramAllocator* allocator =
+          base::GlobalHistogramAllocator::Get();
+      if (allocator)
+        allocator->WriteToPersistentLocation();
+
       is_shutdown_ = true;
     }
   }
 
  protected:
   // True if we have started to initialize the runner.
   bool initialization_started_;
 
   // True if the runner has been shut down.
   bool is_shutdown_;
@@ skipping 12 matching lines @@
 BrowserMainRunner* BrowserMainRunner::Create() {
   return new BrowserMainRunnerImpl();
 }
 
 // static
 bool BrowserMainRunner::ExitedMainMessageLoop() {
   return g_exited_main_message_loop;
 }
 
 }  // namespace content