Simplify threading in browser thread by making only ChromeThread deal with di...

chrome/browser/in_process_webkit/webkit_context.cc

 // Copyright (c) 2009 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/in_process_webkit/webkit_context.h"
 
 #include "chrome/browser/chrome_thread.h"
 
 WebKitContext::WebKitContext(const FilePath& data_path, bool is_incognito)
     : data_path_(data_path),
       is_incognito_(is_incognito),
       ALLOW_THIS_IN_INITIALIZER_LIST(
           dom_storage_context_(new DOMStorageContext(this))) {
 }
 
 WebKitContext::~WebKitContext() {
-  // If the WebKit thread was ever spun up, delete the object there.  If we're
-  // on the IO thread, this is safe because the WebKit thread goes away after
-  // the IO.  If we're on the UI thread, we're safe because the UI thread kills
-  // the WebKit thread.
-  MessageLoop* webkit_loop = ChromeThread::GetMessageLoop(ChromeThread::WEBKIT);
-  if (webkit_loop)
-    webkit_loop->DeleteSoon(FROM_HERE, dom_storage_context_.release());
+  // If the WebKit thread was ever spun up, delete the object there.  The task
+  // will just get deleted if the WebKit thread isn't created.
+  DOMStorageContext* dom_storage_context = dom_storage_context_.release();
+  if (!ChromeThread::DeleteSoon(
+          ChromeThread::WEBKIT, FROM_HERE, dom_storage_context)) {
+    // The WebKit thread wasn't created, and the task got deleted without
+    // freeing the DOMStorageContext, so delete it manually.
+    delete dom_storage_context;

[darin (slow to review), 2009/10/27 00:06:52]

are you sure it is safe to delete this object here?  i believe the
DOMStorageContext references WebKit API objects, which may not be threadsafe. 
you should check with jorlow.

[jam, 2009/10/27 02:38:18]

This preserves the previous logic.

If there's no thread, then dom_storage_context_ was going to get deleted by the
scoped_ptr in this current thread since we're in the destructor.

+  }
 }
 
 void WebKitContext::PurgeMemory() {
   // DOMStorageContext::PurgeMemory() should only be called on the WebKit
   // thread.
   //
   // Note that if there is no WebKit thread, then there's nothing in
-  // LocalStorage and it's OK to no-op here.  Further note that in a unittest,
-  // there may be no threads at all, in which case MessageLoop::current() will
-  // also be NULL and we'll go ahead and call PurgeMemory() directly, which is
-  // probably what the test wants.
-  MessageLoop* webkit_loop = ChromeThread::GetMessageLoop(ChromeThread::WEBKIT);
-  if (MessageLoop::current() == webkit_loop) {
+  // LocalStorage and it's OK to no-op here.
+  if (ChromeThread::CurrentlyOn(ChromeThread::WEBKIT)) {
     dom_storage_context_->PurgeMemory();
-  } else if (webkit_loop) {
+  } else {
     // Since we're not on the WebKit thread, proxy the call over to it.  We
     // can't post a task to call DOMStorageContext::PurgeMemory() directly
     // because that class is not refcounted.
-    webkit_loop->PostTask(FROM_HERE,
-                          NewRunnableMethod(this, &WebKitContext::PurgeMemory));
+    ChromeThread::PostTask(
+        ChromeThread::WEBKIT, FROM_HERE,
+        NewRunnableMethod(this, &WebKitContext::PurgeMemory));
   }
 }