Delay PersistentHistogramAllocator creation until it's known to be used.

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 50 matching lines @@
 
     // On Android we normally initialize the browser in a series of UI thread
     // tasks. While this is happening a second request can come from the OS or
     // another application to start the browser. If this happens then we must
     // not run these parts of initialization twice.
     if (!initialization_started_) {
       initialization_started_ = true;
 
       const base::TimeTicks start_time_step1 = base::TimeTicks::Now();
 
-      // Create persistent/shared memory and allow histograms to be stored in
-      // it. Memory that is not actualy used won't be physically mapped by the
-      // system. BrowserMetrics usage, as reported in UMA, peaked around 1.9MiB
-      // as of 2016-02-20.
-      base::GlobalHistogramAllocator::CreateWithLocalMemory(
-          3 << 20,     // 3 MiB
-          0x935DDD43,  // SHA1(BrowserMetrics)
-          "BrowserMetrics");
-      base::GlobalHistogramAllocator::Disable();  // Enabled by experiment only.
-
       SkGraphics::Init();
 
       if (parameters.command_line.HasSwitch(switches::kWaitForDebugger))
         base::debug::WaitForDebugger(60, true);
 
 #if defined(OS_WIN)
       if (base::win::GetVersion() < base::win::VERSION_VISTA) {
         // When "Extend support of advanced text services to all programs"
         // (a.k.a. Cicero Unaware Application Support; CUAS) is enabled on
         // Windows XP and handwriting modules shipped with Office 2003 are
@@ skipping 155 matching lines @@
 BrowserMainRunner* BrowserMainRunner::Create() {
   return new BrowserMainRunnerImpl();
 }
 
 // static
 bool BrowserMainRunner::ExitedMainMessageLoop() {
   return g_exited_main_message_loop;
 }
 
 }  // namespace content