Consolidate message observer API for win and aura (and touch).

base/message_pump_win.h

Index: base/message_pump_win.h
diff --git a/base/message_pump_win.h b/base/message_pump_win.h
index 5f17610172a13cf2b547aa56799c862860c93959..9da6ac3dce21f77639dc093151aa49db7127e79f 100644
--- a/base/message_pump_win.h
+++ b/base/message_pump_win.h
@@ -19,6 +19,12 @@
 
 namespace base {
 
+typedef MSG NativeEvent;
+
+enum EventStatus {
+  EVENT_CONTINUE,    // The event should be dispatched as normal.
+};
+
 // MessagePumpWin serves as the base for specialized versions of the MessagePump
 // for Windows. It provides basic functionality like handling of observers and
 // controlling the lifetime of the message pump.
@@ -35,11 +41,11 @@ class BASE_EXPORT MessagePumpWin : public MessagePump {
 
     // This method is called before processing a message.
     // The message may be undefined in which case msg.message is 0
-    virtual void WillProcessMessage(const MSG& msg) = 0;
+    virtual EventStatus WillProcessEvent(const NativeEvent& msg) = 0;
 
     // This method is called when control returns from processing a UI message.
     // The message may be undefined in which case msg.message is 0
-    virtual void DidProcessMessage(const MSG& msg) = 0;
+    virtual void DidProcessEvent(const NativeEvent& msg) = 0;
   };
 
   // Dispatcher is used during a nested invocation of Run to dispatch events.
@@ -70,8 +76,8 @@ class BASE_EXPORT MessagePumpWin : public MessagePump {
 
   // Give a chance to code processing additional messages to notify the
   // message loop observers that another message has been processed.
-  void WillProcessMessage(const MSG& msg);
-  void DidProcessMessage(const MSG& msg);
+  void WillProcessEvent(const MSG& msg);
+  void DidProcessEvent(const MSG& msg);
 
   // Like MessagePump::Run, but MSG objects are routed through dispatcher.
   void RunWithDispatcher(Delegate* delegate, Dispatcher* dispatcher);