Initialize webkit thread asynchronously

content/browser/in_process_webkit/webkit_thread.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 "content/browser/in_process_webkit/webkit_thread.h"
 
 #include "base/command_line.h"
 #include "content/browser/in_process_webkit/browser_webkitplatformsupport_impl.h"
 #include "content/public/common/content_switches.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebKit.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebSecurityOrigin.h"
 #include "webkit/glue/webkit_glue.h"
 
 using content::BrowserThread;
 
+// Must be private so that we can carefully control its lifetime. Cannot be
+// anonymous as it is forward-declared in the .h.
+class InternalWebKitThread : public content::BrowserThreadImpl {
+ public:
+  InternalWebKitThread();
+  virtual ~InternalWebKitThread();
+  // Does the actual initialization and shutdown of WebKit.
+  void AsyncInit();
+
+  virtual void Init();
+  virtual void CleanUp();
+
+ private:
+  // The WebKitPlatformSupport implementation.  Only access on WebKit thread.
+  scoped_ptr<BrowserWebKitPlatformSupportImpl> webkit_platform_support_;
+};
+
+// Only used as a parameter in a task sent to itself, so ref-counting
+// is not needed.
+DISABLE_RUNNABLE_METHOD_REFCOUNT(InternalWebKitThread);
+
 WebKitThread::WebKitThread() {
 }
 
 // This happens on the UI thread after the IO thread has been shut down.
 WebKitThread::~WebKitThread() {
   // We can't just check CurrentlyOn(BrowserThread::UI) because in unit tests,
   // MessageLoop::Current is sometimes NULL and other times valid and there's
   // no BrowserThread object.  Can't check that CurrentlyOn is not IO since
   // some unit tests set that BrowserThread for other checks.
   DCHECK(!BrowserThread::CurrentlyOn(BrowserThread::WEBKIT));
 }
 
 void WebKitThread::Initialize() {
   DCHECK(!webkit_thread_.get());
 
   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kSingleProcess)) {
     // TODO(jorlow): We need a better story for single process mode.
     return;
   }
 
   webkit_thread_.reset(new InternalWebKitThread);
   bool started = webkit_thread_->Start();
   DCHECK(started);
+  BrowserThread::PostTask(BrowserThread::WEBKIT, FROM_HERE, NewRunnableMethod(
+      webkit_thread_.get(),
+      &InternalWebKitThread::AsyncInit));
 }
 
-WebKitThread::InternalWebKitThread::InternalWebKitThread()
+InternalWebKitThread::InternalWebKitThread()
     : content::BrowserThreadImpl(BrowserThread::WEBKIT) {
 }
 
-WebKitThread::InternalWebKitThread::~InternalWebKitThread() {
+InternalWebKitThread::~InternalWebKitThread() {
   Stop();
 }
 
-void WebKitThread::InternalWebKitThread::Init() {
+void InternalWebKitThread::AsyncInit() {
   DCHECK(!webkit_platform_support_.get());
   webkit_platform_support_.reset(new BrowserWebKitPlatformSupportImpl);
   WebKit::initializeWithoutV8(webkit_platform_support_.get());
   webkit_glue::EnableWebCoreLogChannels(
       CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
           switches::kWebCoreLogChannels));
   // Exercise WebSecurityOrigin to get its underlying statics initialized.
   // TODO(michaeln): remove this when the following is landed.
   // https://bugs.webkit.org/show_bug.cgi?id=61145
   WebKit::WebSecurityOrigin::create(GURL("http://chromium.org"));
-
-  // If possible, post initialization tasks to this thread (rather than doing
-  // them now) so we don't block the UI thread any longer than we have to.
 }
 
-void WebKitThread::InternalWebKitThread::CleanUp() {
+void InternalWebKitThread::Init() {
+  // Any work done here blocks the caller; as WebKit::initialize... takes time
+  // to complete we do it in the cutom async variant above instead.
+}
+
+void InternalWebKitThread::CleanUp() {
   DCHECK(webkit_platform_support_.get());
   WebKit::shutdown();
 }