Disable ThreadWatcher in CANARY and UNKNOWN channels temporarily to measure its

chrome/browser/metrics/thread_watcher.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 "chrome/browser/metrics/thread_watcher.h"
 
 #include <math.h>  // ceil
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
@@ skipping 518 matching lines @@
       BrowserThread::UI,
       FROM_HERE,
       base::Bind(&StartupTimeBomb::DisarmStartupTimeBomb));
 
   // This method is deferred in relationship to its StopWatchingAll()
   // counterpart. If a previous initialization has already happened, or if
   // stop has been called, there's nothing left to do here.
   if (g_thread_watcher_list_ || g_stopped_)
     return;
 
+  // Disable ThreadWatcher in Canary channel.
+  chrome::VersionInfo::Channel channel = chrome::VersionInfo::GetChannel();
+  if (channel == chrome::VersionInfo::CHANNEL_CANARY ||
+      channel == chrome::VersionInfo::CHANNEL_UNKNOWN)

[Alexei Svitkine (slow), 2015/04/28 16:38:38]

Nit: {}'s

[ramant (doing other things), 2015/04/28 17:06:35]

Done.

+    return;
+
   ThreadWatcherList* thread_watcher_list = new ThreadWatcherList();
   CHECK(thread_watcher_list);
 
   const base::TimeDelta kSleepTime =
       base::TimeDelta::FromSeconds(kSleepSeconds);
   const base::TimeDelta kUnresponsiveTime =
       base::TimeDelta::FromSeconds(kUnresponsiveSeconds);
 
   StartWatching(BrowserThread::UI, "UI", kSleepTime, kUnresponsiveTime,
                 unresponsive_threshold, crash_on_hang_threads);
@@ skipping 372 matching lines @@
 
 #if defined(OS_WIN)
   // On Windows XP, give twice the time for shutdown.
   if (base::win::GetVersion() <= base::win::VERSION_XP)
     actual_duration *= 2;
 #endif
 
   shutdown_watchdog_ = new ShutdownWatchDogThread(actual_duration);
   shutdown_watchdog_->Arm();
 }