Fixed the memory leak of callback Task in PostPingMessage....

chrome/browser/metrics/thread_watcher.cc

 // 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.
 
 #include "base/threading/thread_restrictions.h"
 #include "chrome/browser/metrics/metrics_service.h"
 #include "chrome/browser/metrics/thread_watcher.h"
 #include "chrome/common/notification_service.h"
 
 // static
@@ skipping 86 matching lines @@
   // ping messages.
   if (!active_ || ping_count_ <= 0)
     return;
 
   // Save the current time when we have sent ping message.
   ping_time_ = base::TimeTicks::Now();
 
   // Send a ping message to the watched thread.
   Task* callback_task = method_factory_.NewRunnableMethod(
       &ThreadWatcher::OnPongMessage, ping_sequence_number_);
-  BrowserThread::PostTask(
-      thread_id(),
-      FROM_HERE,
-      NewRunnableFunction(
-          &ThreadWatcher::OnPingMessage, thread_id_, callback_task));
-
-  // Post a task to check the responsiveness of watched thread.
-  MessageLoop::current()->PostDelayedTask(
-      FROM_HERE,
-      method_factory_.NewRunnableMethod(
-          &ThreadWatcher::OnCheckResponsiveness, ping_sequence_number_),
-      unresponsive_time_.InMilliseconds());
+  if (BrowserThread::PostTask(
+          thread_id(),
+          FROM_HERE,
+          NewRunnableFunction(
+              &ThreadWatcher::OnPingMessage, thread_id_, callback_task))) {
+      // Post a task to check the responsiveness of watched thread.
+      MessageLoop::current()->PostDelayedTask(
+          FROM_HERE,
+          method_factory_.NewRunnableMethod(
+              &ThreadWatcher::OnCheckResponsiveness, ping_sequence_number_),
+          unresponsive_time_.InMilliseconds());
+  } else {
+    // Watched thread might have gone away, stop watching it.
+    delete callback_task;
+    DeActivateThreadWatching();
+  }
 }
 
 void ThreadWatcher::OnPongMessage(uint64 ping_sequence_number) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::WATCHDOG));
   // Record watched thread's response time.
   base::TimeDelta response_time = base::TimeTicks::Now() - ping_time_;
   histogram_->AddTime(response_time);
 
   // Check if there are any extra pings in flight.
   DCHECK_EQ(ping_sequence_number_, ping_sequence_number);
@@ skipping 182 matching lines @@
                                kUnresponsiveTime);
   ThreadWatcher::StartWatching(BrowserThread::IO, "IO", kSleepTime,
                                kUnresponsiveTime);
   ThreadWatcher::StartWatching(BrowserThread::DB, "DB", kSleepTime,
                                kUnresponsiveTime);
   ThreadWatcher::StartWatching(BrowserThread::FILE, "FILE", kSleepTime,
                                kUnresponsiveTime);
   ThreadWatcher::StartWatching(BrowserThread::CACHE, "CACHE", kSleepTime,
                                kUnresponsiveTime);
 }