DOM Storage: Add browser-process IPC code + tweak the WebKit Thread.

chrome/browser/in_process_webkit/webkit_thread.cc

Index: chrome/browser/in_process_webkit/webkit_thread.cc
===================================================================
--- chrome/browser/in_process_webkit/webkit_thread.cc	(revision 21342)
+++ chrome/browser/in_process_webkit/webkit_thread.cc	(working copy)
@@ -10,15 +10,43 @@
 #include "webkit/api/public/WebKit.h"
 
 // This happens on the UI thread before the IO thread has been shut down.
-WebKitThread::WebKitThread() {
+WebKitThread::WebKitThread()
+    : io_message_loop_(ChromeThread::GetMessageLoop(ChromeThread::IO)) {
   // The thread is started lazily by InitializeThread() on the IO thread.
 }
 
 // This happens on the UI thread after the IO thread has been shut down.
 WebKitThread::~WebKitThread() {
+  // There's no good way to see if we're on the UI thread.
   DCHECK(!ChromeThread::CurrentlyOn(ChromeThread::WEBKIT));
+  DCHECK(!ChromeThread::CurrentlyOn(ChromeThread::IO));
+  DCHECK(!io_message_loop_);
 }
 
+void WebKitThread::Shutdown() {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::IO));
+  DCHECK(io_message_loop_);
+
+  // TODO(jorlow): Start flushing LocalStorage?
+
+  AutoLock lock(io_message_loop_lock_);
+  io_message_loop_ = NULL;
+}
+
+bool WebKitThread::PostIOThreadTask(
+    const tracked_objects::Location& from_here, Task* task) {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::WEBKIT));
+  {
+    AutoLock lock(io_message_loop_lock_);
+    if (io_message_loop_) {
+      io_message_loop_->PostTask(from_here, task);
+      return true;
+    }
+  }
+  delete task;
+  return false;
+}
+
 WebKitThread::InternalWebKitThread::InternalWebKitThread()
     : ChromeThread(ChromeThread::WEBKIT),
       webkit_client_(NULL) {
@@ -29,13 +57,12 @@
   webkit_client_ = new BrowserWebKitClientImpl;
   DCHECK(webkit_client_);
   WebKit::initialize(webkit_client_);
-  // Don't do anything heavyweight here since this can block the IO thread from
-  // executing (since InitializeThread() is called on the IO thread).
+  // If possible, post initialization tasks to this thread (rather than doing
+  // them now) so we don't block the IO thread any longer than we have to.
 }
 
 void WebKitThread::InternalWebKitThread::CleanUp() {
-  // Don't do anything heavyweight here since this can block the IO thread from
-  // executing (since the thread is shutdown from the IO thread).
+  // TODO(jorlow): Block on LocalStorage being 100% shut down.
   DCHECK(webkit_client_);
   WebKit::shutdown();
   delete webkit_client_;
@@ -45,6 +72,7 @@
   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kSingleProcess))
     return NULL;
 
+  DCHECK(io_message_loop_);
   DCHECK(!webkit_thread_.get());
   webkit_thread_.reset(new InternalWebKitThread);
   bool started = webkit_thread_->Start();