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

content/browser/renderer_host/render_widget_host_view_win.h

Index: content/browser/renderer_host/render_widget_host_view_win.h
diff --git a/content/browser/renderer_host/render_widget_host_view_win.h b/content/browser/renderer_host/render_widget_host_view_win.h
index 0f68b427d2637cec8eb498c1605213a506f61529..2ae7c0ba476aa3431bccbf9bb92798898eb0e273 100644
--- a/content/browser/renderer_host/render_widget_host_view_win.h
+++ b/content/browser/renderer_host/render_widget_host_view_win.h
@@ -178,6 +178,8 @@ class RenderWidgetHostViewWin
   virtual void OnAccessibilityNotifications(
       const std::vector<ViewHostMsg_AccessibilityNotification_Params>& params
       ) OVERRIDE;
+  virtual bool LockMouse() OVERRIDE;
+  virtual void UnlockMouse() OVERRIDE;
 
   // Implementation of NotificationObserver:
   virtual void Observe(int type,
@@ -288,6 +290,11 @@ class RenderWidgetHostViewWin
                                const gfx::Rect& pos,
                                DWORD ex_style);
 
+  CPoint GetClientCenter() const;
+  void MoveCursorToCenter() const;
+
+  void HandleLockedMouseEvent(UINT message, WPARAM wparam, LPARAM lparam);
+
   // The associated Model.  While |this| is being Destroyed,
   // |render_widget_host_| is NULL and the Windows message loop is run one last
   // time. Message handlers must check for a NULL |render_widget_host_|.
@@ -383,6 +390,20 @@ class RenderWidgetHostViewWin
   // Is the widget fullscreen?
   bool is_fullscreen_;
 
+  // Used to record the last position of the mouse.
+  // While the mouse is locked, they store the last known position just as mouse
+  // lock was entered.
+  // Relative to the upper-left corner of the view.
+  int last_x_;

[brettw, 2011/09/14 22:17:58]

Can you use a gfx::Point for both of these cases? It will handle initialization
to 0 in the constructor and also remove one extra member variable. Maybe you
could even use end-of-line comments for the "Relative to..." comments and then
everything is only 2 lines.

[yzshen1, 2011/09/19 20:48:41]

Done. (Didn't use end-of-line comments because I cannot fit them in the same
line as the definitions now.)

+  int last_y_;
+  // Relative to the upper-left corner of the screen.
+  int last_global_x_;
+  int last_global_y_;
+
+  // In the case of the mouse being moved away from the view and then moved
+  // back, we regard the mouse movement as (0, 0).
+  bool ignore_mouse_movement_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewWin);
 };