Pepper: Introduce ThreadAwareCallback.

ppapi/shared_impl/thread_aware_callback.cc

Index: ppapi/shared_impl/thread_aware_callback.cc
diff --git a/ppapi/shared_impl/thread_aware_callback.cc b/ppapi/shared_impl/thread_aware_callback.cc
new file mode 100644
index 0000000000000000000000000000000000000000..7aa877e84a1b3138da28d784a7b507b7ca1f45b9
--- /dev/null
+++ b/ppapi/shared_impl/thread_aware_callback.cc
@@ -0,0 +1,60 @@
+// 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 "ppapi/shared_impl/thread_aware_callback.h"
+
+#include "base/callback.h"
+#include "ppapi/shared_impl/ppapi_globals.h"
+#include "ppapi/shared_impl/ppb_message_loop_shared.h"
+
+namespace ppapi {
+namespace internal {
+
+class ThreadAwareCallbackBase::Core : public base::RefCountedThreadSafe<Core> {
+ public:
+  Core() : aborted_(false) {
+  }
+
+  void MarkAsAborted() { aborted_ = true; }
+
+  void RunIfNotAborted(const base::Closure& closure) {
+    // This method is a posted task and run while the proxy lock is not
+    // acquired, so we have to acquire the lock in order to access |aborted_|.
+    ProxyAutoLock auto_lock;
+
+    if (!aborted_)
+      CallWhileUnlocked(closure);
+  }
+
+ private:
+  friend class base::RefCountedThreadSafe<Core>;
+  ~Core() {
+  }
+
+  bool aborted_;
+};
+
+ThreadAwareCallbackBase::ThreadAwareCallbackBase()
+    : target_loop_(PpapiGlobals::Get()->GetCurrentMessageLoop()),
+      core_(new Core()) {
+}
+
+ThreadAwareCallbackBase::~ThreadAwareCallbackBase() {
+  core_->MarkAsAborted();
+}
+
+bool ThreadAwareCallbackBase::ShouldPostToTargetLoop() {
+  return target_loop_.get() &&
+         target_loop_ != PpapiGlobals::Get()->GetCurrentMessageLoop();
+}
+
+void ThreadAwareCallbackBase::RunIfNotAborted(
+    const base::Closure& closure) {
+  target_loop_->PostClosure(FROM_HERE,
+                            base::Bind(&Core::RunIfNotAborted, core_, closure),
+                            0);
+}
+
+}  // namespace internal
+}  // namespace ppapi