Support custom V8 bindings on WebWorker threads (issue #451).

- Add CefRenderProcessHandler callbacks for WebWorker context creation, release and uncaught exceptions.
- Add CefTaskRunner class that supports posting of tasks to standard threads and WebWorker threads.
- Organize V8 internal state information on a per-thread/per-Isolate basis.
- Add webkit_451.patch that provides the WebKit implementation.

git-svn-id: https://chromiumembedded.googlecode.com/svn/trunk@972 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

include/cef_task.h

@@ -1,4 +1,4 @@
-// Copyright (c) 2012 Marshall A. Greenblatt. All rights reserved.
+// Copyright (c) 2013 Marshall A. Greenblatt. All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
@@ -39,50 +39,110 @@
 
 #include "include/cef_base.h"
 
-class CefTask;
-
 typedef cef_thread_id_t CefThreadId;
 
 ///
+// Implement this interface for asynchronous task execution. If the task is
+// posted successfully and if the associated message loop is still running then
+// the Execute() method will be called on the target thread. If the task fails
+// to post then the task object may be destroyed on the source thread instead of
+// the target thread. For this reason be cautious when performing work in the
+// task object destructor.
+///
+/*--cef(source=client)--*/
+class CefTask : public virtual CefBase {
+ public:
+  ///
+  // Method that will be executed on the target thread.
+  ///
+  /*--cef()--*/
+  virtual void Execute() =0;
+};
+
+///
+// Class that asynchronously executes tasks on the associated thread. It is safe
+// to call the methods of this class on any thread.
+//
 // CEF maintains multiple internal threads that are used for handling different
-// types of tasks in different processes. See the cef_thread_id_t definitions in
-// cef_types.h for more information. This function will return true if called on
-// the specified thread. It is an error to request a thread from the wrong
-// process.
+// types of tasks in different processes. The cef_thread_id_t definitions in
+// cef_types.h list the common CEF threads. Task runners are also available for
+// other CEF threads as appropriate (for example, V8 WebWorker threads).
+///
+/*--cef(source=library)--*/
+class CefTaskRunner : public virtual CefBase {
+ public:
+  ///
+  // Returns the task runner for the current thread. Only CEF threads will have
+  // task runners. An empty reference will be returned if this method is called
+  // on an invalid thread.
+  ///
+  /*--cef()--*/
+  static CefRefPtr<CefTaskRunner> GetForCurrentThread();
+
+  ///
+  // Returns the task runner for the specified CEF thread.
+  ///
+  /*--cef()--*/
+  static CefRefPtr<CefTaskRunner> GetForThread(CefThreadId threadId);
+
+  ///
+  // Returns true if this object is pointing to the same task runner as |that|
+  // object.
+  ///
+  /*--cef()--*/
+  virtual bool IsSame(CefRefPtr<CefTaskRunner> that) =0;
+
+  ///
+  // Returns true if this task runner belongs to the current thread.
+  ///
+  /*--cef()--*/
+  virtual bool BelongsToCurrentThread() =0;
+
+  ///
+  // Returns true if this task runner is for the specified CEF thread.
+  ///
+  /*--cef()--*/
+  virtual bool BelongsToThread(CefThreadId threadId) =0;
+
+  ///
+  // Post a task for execution on the thread associated with this task runner.
+  // Execution will occur asynchronously.
+  ///
+  /*--cef()--*/
+  virtual bool PostTask(CefRefPtr<CefTask> task) =0;
+
+  ///
+  // Post a task for delayed execution on the thread associated with this task
+  // runner. Execution will occur asynchronously. Delayed tasks are not
+  // supported on V8 WebWorker threads and will be executed without the
+  // specified delay.
+  ///
+  /*--cef()--*/
+  virtual bool PostDelayedTask(CefRefPtr<CefTask> task, int64 delay_ms) =0;
+};
+
+
+///
+// Returns true if called on the specified thread. Equivalent to using
+// CefTaskRunner::GetForThread(threadId)->BelongsToCurrentThread().
 ///
 /*--cef()--*/
 bool CefCurrentlyOn(CefThreadId threadId);
 
 ///
-// Post a task for execution on the specified thread. This function may be
-// called on any thread. It is an error to request a thread from the wrong
-// process.
+// Post a task for execution on the specified thread. Equivalent to
+// using CefTaskRunner::GetForThread(threadId)->PostTask(task).
 ///
 /*--cef()--*/
 bool CefPostTask(CefThreadId threadId, CefRefPtr<CefTask> task);
 
 ///
-// Post a task for delayed execution on the specified thread. This function may
-// be called on any thread. It is an error to request a thread from the wrong
-// process.
+// Post a task for delayed execution on the specified thread. Equivalent to
+// using CefTaskRunner::GetForThread(threadId)->PostDelayedTask(task, delay_ms).
 ///
 /*--cef()--*/
 bool CefPostDelayedTask(CefThreadId threadId, CefRefPtr<CefTask> task,
                         int64 delay_ms);
 
 
-///
-// Implement this interface for task execution. The methods of this class may
-// be called on any thread.
-///
-/*--cef(source=client)--*/
-class CefTask : public virtual CefBase {
- public:
-  ///
-  // Method that will be executed. |threadId| is the thread executing the call.
-  ///
-  /*--cef()--*/
-  virtual void Execute(CefThreadId threadId) =0;
-};
-
 #endif  // CEF_INCLUDE_CEF_TASK_H_