Revert "Send input event IPCs directly from the UI thread"

ipc/ipc_channel_proxy.h

Index: ipc/ipc_channel_proxy.h
diff --git a/ipc/ipc_channel_proxy.h b/ipc/ipc_channel_proxy.h
index c28ba2f0940045362f905a9665bf84f7a86ecc0e..0c9323304098c2fc18c75f247479a749b1d3f27b 100644
--- a/ipc/ipc_channel_proxy.h
+++ b/ipc/ipc_channel_proxy.h
@@ -123,24 +123,10 @@ class IPC_EXPORT ChannelProxy : public Endpoint, public base::NonThreadSafe {
   // with / allow for this possibility.
   void Close();
 
-  // DEPRECATED: Please use either SendNow or SendOnIPCThread to make ordering
-  // expectations explicit.
-  //
-  // This is an alias for for SendOnIPCThread.
+  // Send a message asynchronously.  The message is routed to the background
+  // thread where it is passed to the IPC::Channel's Send method.
   bool Send(Message* message) override;
 
-  // Send a message as soon as possible. This method may send the message
-  // immediately, or it may defer and send on the IPC thread. Use this when you
-  // you don't care about strict ordering of the send operation with respect to
-  // tasks on the IPC thread. This is most commonly what you want.
-  virtual bool SendNow(std::unique_ptr<Message> message);
-
-  // Send a message from the IPC thread. This immediately posts a task to the
-  // IPC thread task runner to send the message. Use this when you're posting
-  // other related tasks to the IPC thread and you need to guarantee that the
-  // send operation is ordered with respect to those tasks.
-  virtual bool SendOnIPCThread(std::unique_ptr<Message> message);
-
   // Used to intercept messages as they are received on the background thread.
   //
   // Ordinarily, messages sent to the ChannelProxy are routed to the matching
@@ -195,7 +181,7 @@ class IPC_EXPORT ChannelProxy : public Endpoint, public base::NonThreadSafe {
     void OnDispatchMessage(const Message& message);
 
     // Sends |message| from appropriate thread.
-    bool Send(std::unique_ptr<Message> message, bool force_io_thread);
+    void Send(Message* message);
 
     // Indicates if the underlying channel's Send is thread-safe.
     bool IsChannelSendThreadSafe() const;
@@ -249,6 +235,7 @@ class IPC_EXPORT ChannelProxy : public Endpoint, public base::NonThreadSafe {
     void OnDispatchError();
     void OnDispatchBadMessage(const Message& message);
 
+    void SendFromThisThread(Message* message);
     void ClearChannel();
 
     scoped_refptr<base::SingleThreadTaskRunner> listener_task_runner_;
@@ -309,8 +296,6 @@ class IPC_EXPORT ChannelProxy : public Endpoint, public base::NonThreadSafe {
   // Always called once immediately after Init.
   virtual void OnChannelInit();
 
-  bool SendImpl(std::unique_ptr<Message> message, bool force_io_thread);
-
   // By maintaining this indirection (ref-counted) to our internal state, we
   // can safely be destroyed while the background thread continues to do stuff
   // that involves this data.