Add PluginMessageLoopProxy and use it for Host plugin UI thread.

remoting/base/plugin_message_loop_proxy.h

Index: remoting/base/plugin_message_loop_proxy.h
diff --git a/remoting/base/plugin_message_loop_proxy.h b/remoting/base/plugin_message_loop_proxy.h
new file mode 100644
index 0000000000000000000000000000000000000000..7b2eef2a0b45d016c4be3ade06b36721f82d56e9
--- /dev/null
+++ b/remoting/base/plugin_message_loop_proxy.h
@@ -0,0 +1,80 @@
+// 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.
+
+#ifndef REMOTING_BASE_PLUGIN_MESSAGE_LOOP_H_
+#define REMOTING_BASE_PLUGIN_MESSAGE_LOOP_H_
+
+#include "base/callback.h"
+#include "base/compiler_specific.h"
+#include "base/message_loop_proxy.h"
+#include "base/synchronization/lock.h"
+
+namespace remoting {
+
+// MessageLoopProxy for plugin main threads.
+class PluginMessageLoopProxy : public base::MessageLoopProxy {
+ public:
+  class Delegate {
+   public:
+    Delegate() { }
+    virtual ~Delegate() { }
+
+    virtual bool RunOnPluginThread(
+        int delay_ms, void(function)(void*), void* data) = 0;
+    virtual bool IsPluginThread() = 0;
+  };
+
+  // Caller keeps ownership of delegate.
+  PluginMessageLoopProxy(Delegate* delegate);
+  virtual ~PluginMessageLoopProxy();
+
+  void Detach();
+
+  // base::MessageLoopProxy interface.
+  virtual bool PostTask(
+      const tracked_objects::Location& from_here,
+      Task* task) OVERRIDE;
+  virtual bool PostDelayedTask(
+      const tracked_objects::Location& from_here,
+      Task* task,
+      int64 delay_ms) OVERRIDE;
+  virtual bool PostNonNestableTask(
+      const tracked_objects::Location& from_here,
+      Task* task) OVERRIDE;
+  virtual bool PostNonNestableDelayedTask(
+      const tracked_objects::Location& from_here,
+      Task* task,
+      int64 delay_ms) OVERRIDE;
+
+  virtual bool PostTask(
+      const tracked_objects::Location& from_here,
+      const base::Closure& task) OVERRIDE;
+  virtual bool PostDelayedTask(
+      const tracked_objects::Location& from_here,
+      const base::Closure& task,
+      int64 delay_ms) OVERRIDE;
+  virtual bool PostNonNestableTask(
+      const tracked_objects::Location& from_here,
+      const base::Closure& task) OVERRIDE;
+  virtual bool PostNonNestableDelayedTask(
+      const tracked_objects::Location& from_here,
+      const base::Closure& task,
+      int64 delay_ms) OVERRIDE;
+
+  virtual bool BelongsToCurrentThread() OVERRIDE;
+
+ private:
+  // |lock_| must be acquired when accessing |delegate_|.
+  base::Lock lock_;
+  Delegate* delegate_;
+
+  static void RunTask(void* data);
+  static void RunClosure(void* data);
+
+  DISALLOW_COPY_AND_ASSIGN(PluginMessageLoopProxy);
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_BASE_PLUGIN_MESSAGE_LOOP_H_