Revert "Reverting 23406" as it didn't break any tests....

base/window_impl.h

Index: base/window_impl.h
===================================================================
--- base/window_impl.h	(revision 23441)
+++ base/window_impl.h	(working copy)
@@ -18,6 +18,19 @@
 
 namespace base {
 
+// An interface implemented by classes that use message maps.
+// ProcessWindowMessage is implemented by the BEGIN_MESSAGE_MAP_EX macro.
+class MessageMapInterface {
+ public:
+  // Processes one message from the window's message queue.
+  virtual BOOL ProcessWindowMessage(HWND window,
+                                    UINT message,
+                                    WPARAM w_param,
+                                    LPARAM l_param,
+                                    LRESULT& result,
+                                    DWORD msg_mad_id = 0) = 0;
+};
+
 ///////////////////////////////////////////////////////////////////////////////
 //
 // WindowImpl
@@ -26,24 +39,20 @@
 //  Windows.
 //
 ///////////////////////////////////////////////////////////////////////////////
-class WindowImpl {
+class WindowImpl : public MessageMapInterface {
  public:
   WindowImpl();
   virtual ~WindowImpl();
 
-  BEGIN_MSG_MAP_EX(WindowImpl)
-    // No messages to handle
-  END_MSG_MAP()
+  // Initializes the Window with a parent and an initial desired size.
+  void Init(HWND parent, const gfx::Rect& bounds);
 
-  // Initialize the Window with a parent and an initial desired size.
-  virtual void Init(HWND parent, const gfx::Rect& bounds);
-
-  // Returns the gfx::NativeView associated with this Window.
-  virtual gfx::NativeView GetNativeView() const;
-
   // Retrieves the default window icon to use for windows if none is specified.
   virtual HICON GetDefaultWindowIcon() const;
 
+  // Returns the HWND associated with this Window.
+  HWND hwnd() const { return hwnd_; }
+
   // Sets the window styles. This is ONLY used when the window is created.
   // In other words, if you invoke this after invoking Init, nothing happens.
   void set_window_style(DWORD style) { window_style_ = style; }
@@ -62,16 +71,13 @@
   UINT initial_class_style() { return class_style_; }
 
  protected:
-  // Call close instead of this to Destroy the window.
-  BOOL DestroyWindow();
-
   // Handles the WndProc callback for this object.
   virtual LRESULT OnWndProc(UINT message, WPARAM w_param, LPARAM l_param);
 
  private:
   friend class ClassRegistrar;
 
-  // The windows procedure used by all Windows.
+  // The window procedure used by all Windows.
   static LRESULT CALLBACK WndProc(HWND window,
                                   UINT message,
                                   WPARAM w_param,