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 84 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();

[willchan no longer on Chromium, 2011/02/23 23:39:02]

I have not re-read the changelist since the last round of big changes, so you
should get Jim to look at this. In particular, I'm don't know if
DeActivateThreadWatching() is correct here. It probably is, I just don't know
since I forgot how the CL works :)

+  }
 }
 
 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);
 }