Only wait for CancelAllRequests done if the post task succeeds

chrome/browser/history/android/sqlite_cursor.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/history/android/sqlite_cursor.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/bind.h"
@@ skipping 138 matching lines @@
       test_observer_(NULL) {
 }
 
 SQLiteCursor::~SQLiteCursor() {
   // Consumer requests were set in the UI thread. They must be cancelled
   // using the same thread.
   if (BrowserThread::CurrentlyOn(BrowserThread::UI)) {
     CancelAllRequests(NULL);
   } else {
     base::WaitableEvent event(false, false);
-    BrowserThread::PostTask(
-        BrowserThread::UI,
-        FROM_HERE,
+    if (BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,

[sky, 2013/05/30 19:33:05]

From PostTask: " even if the task is posted, there's no guarantee that it will
run, since the target thread may already have a Quit message in its queue."

Does this code need to deal with the case of the UI messageloop not running or
in the process of shutting down?

[michaelbai, 2013/05/31 05:17:02]

In the case of UI message loop goes away, the whole process will be destroyed
soon, we don't care about deleting objects.
The SQLitCursor(this pointer) could be destroy from UI thread, so I removed the
wait event, put cleanup code into DestroyOnUIThread, and hope it get chance to
run, the Java code will not wait the cursor be destroyed any more.

I also modified unit test to reflect this change.

On 2013/05/30 19:33:05, sky wrote:

         base::Bind(&SQLiteCursor::CancelAllRequests, base::Unretained(this),
-                   &event));
-    event.Wait();
+                   &event))) {
+      event.Wait();
+    }
   }
 
   BrowserThread::PostTask(
       BrowserThread::UI,
       FROM_HERE,
       base::Bind(&AndroidHistoryProviderService::CloseStatement,
                  base::Unretained(service_), statement_));
 }
 
 bool SQLiteCursor::GetFavicon(chrome::FaviconID id,
@@ skipping 70 matching lines @@
 }
 
 void SQLiteCursor::RunMoveStatementOnUIThread(int pos) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   if (!consumer_.get())
     consumer_.reset(new CancelableRequestConsumer());
   service_->MoveStatement(
       statement_, position_, pos, consumer_.get(),
       base::Bind(&SQLiteCursor::OnMoved, base::Unretained(this)));
 }