Add a new pair of IPC categories for messages that need handling as input events

The compositor thread input filtering mechanism adds the possibility of
handling some IPCs in the render process main thread in a different order than
they were sent from the browser process since it filters some messages from the
IO thread.  For the most part, this is OK since the exact order of different
types of messages is not important but there are some input-related messages
that do need to processed in order - for instance MouseCaptureLost
(see crbug.com/231532).

This adds a new IPC class, InputMsg, for messages that need input-like
filtering and InputHostMsg for their ACKs. All messages of this class are
routed through the compositor thread to preserve order.

BUG=233365

Review URL: https://chromiumcodereview.appspot.com/14487003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@196907 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/content/renderer/render_widget.h b/content/renderer/render_widget.h
index fdc8909..fe3e9f1 100644
--- a/content/renderer/render_widget.h
+++ b/content/renderer/render_widget.h
@@ -279,6 +279,10 @@
               ResizeAck resize_ack);
 
   // RenderWidget IPC message handlers
+  void OnHandleInputEvent(const WebKit::WebInputEvent* event,
+                          bool keyboard_shortcut);
+  void OnMouseCaptureLost();
+  virtual void OnSetFocus(bool enable);
   void OnClose();
   void OnCreatingNewAck();
   virtual void OnResize(const gfx::Size& new_size,
@@ -294,10 +298,6 @@
   void OnCreateVideoAck(int32 video_id);
   void OnUpdateVideoAck(int32 video_id);
   void OnRequestMoveAck();
-  void OnHandleInputEvent(const WebKit::WebInputEvent* event,
-                          bool keyboard_shortcut);
-  void OnMouseCaptureLost();
-  virtual void OnSetFocus(bool enable);
   void OnSetInputMethodActive(bool is_active);
   virtual void OnImeSetComposition(
       const string16& text,