Refactor BaseTimer to avoid spamming the MessageLoop with orphaned tasks.

This change maintains the same API promises*, but instead of orphaning tasks when they are stopped, the BaseTimer_Helper class holds on to the task until either (1) it expires or (2) the user requests a delay that would arrive earlier than the pending task. If the user requests a longer delay than the pending task, a followup task will be posted when the pending task fires to span the remaining time.

* The one change of usage is related to threading. The threading requirements are now more strict. It is not allowed to destruct a timer on a different thread than the one used to post tasks. A thread ID DCHECK is now in place that will help catch misuse. Some existing instances are changed as part of this CL.

A side effect of this change is that the BaseTimer and DelayTimer are simplified to use features of BaseTimer_Helper (which is now called Timer).

As suggested in timer.h, I ran the disabled TimerTest tests from linux, and they pass consistently. I also added some new tests to verify correct run states.

BUG=117451,103667,119714,119750

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=128412

Reverted: http://src.chromium.org/viewvc/chrome?view=rev&revision=128506

Review URL: https://chromiumcodereview.appspot.com/9655006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@128993 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 5 insertions, 1 deletions

diff --git a/content/browser/in_process_webkit/webkit_thread.cc b/content/browser/in_process_webkit/webkit_thread.cc
index bb1ae40..db0cd07 100644
--- a/content/browser/in_process_webkit/webkit_thread.cc
+++ b/content/browser/in_process_webkit/webkit_thread.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -66,6 +66,10 @@ void WebKitThread::InternalWebKitThread::Init() {
 void WebKitThread::InternalWebKitThread::CleanUp() {
   DCHECK(webkit_platform_support_.get());
   WebKit::shutdown();
+  // Delete BrowserWebKitPlatformSupportImpl now while on the same thread that
+  // constructed it. (This prevents the WebKit shared timer from being destroyed
+  // on a different thread than the one using it.)
+  webkit_platform_support_.reset();
 }
 
 }  // namespace content