Mouse lock implementation, including the renderer side and the Windows version of the browser side.

content/renderer/render_widget.h

Index: content/renderer/render_widget.h
diff --git a/content/renderer/render_widget.h b/content/renderer/render_widget.h
index 05a7d5fcebaab2579ba321ed517f72de000ffac6..563c7ca5390b3b461773b6fc3960a3ff0af3eeef 100644
--- a/content/renderer/render_widget.h
+++ b/content/renderer/render_widget.h
@@ -42,6 +42,7 @@ class PlatformCanvas;
 }
 
 namespace WebKit {
+class WebInputEvent;
 class WebMouseEvent;
 class WebWidget;
 struct WebPopupMenuInfo;
@@ -304,6 +305,13 @@ class RenderWidget : public IPC::Channel::Listener,
   // just handled.
   virtual void DidHandleMouseEvent(const WebKit::WebMouseEvent& event) {}
 
+  // Called by OnHandleInputEvent() to notify subclasses that an input event is
+  // about to be handled.
+  // Returns true if the event has been handled by subclasses.
+  virtual bool OnBeforeHandleInputEvent(const WebKit::WebInputEvent& event) {
+    return false;
+  }
+
   // Routing ID that allows us to communicate to the parent browser process
   // RenderWidgetHost. When MSG_ROUTING_NONE, no messages may be sent.
   int32 routing_id_;