Fix mouse lock perf issue on Windows.

content/browser/renderer_host/render_widget_host_view_win.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_WIN_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_WIN_H_
 #pragma once
 
 #include <atlbase.h>
 #include <atlapp.h>
@@ skipping 317 matching lines @@
 
   // Whether the window should be activated.
   bool IsActivatable() const;
 
   // Do initialization needed by both InitAsPopup() and InitAsFullscreen().
   void DoPopupOrFullscreenInit(HWND parent_hwnd,
                                const gfx::Rect& pos,
                                DWORD ex_style);
 
   CPoint GetClientCenter() const;
-  void MoveCursorToCenter() const;
+  // In mouse lock mode, moves the mouse cursor to the center of the view if it
+  // is too close to the border.
+  void MoveCursorToCenterIfNecessary();
 
   void HandleLockedMouseEvent(UINT message, WPARAM wparam, LPARAM lparam);
 
   LRESULT OnDocumentFeed(RECONVERTSTRING* reconv);
   LRESULT OnReconvertString(RECONVERTSTRING* reconv);
 
   // 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_|.
   RenderWidgetHost* render_widget_host_;
@@ skipping 123 matching lines @@
   // Stores the current text input type received by TextInputStateChanged()
   // method.
   ui::TextInputType text_input_type_;
 
   ScopedVector<ui::ViewProp> props_;
 
   // 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.
+  // While the mouse is locked, |last_unlocked_mouse_position_| and
+  // |last_unlocked_global_mouse_position_| store the last known position just
+  // as mouse lock was entered.
   // Relative to the upper-left corner of the view.
-  gfx::Point last_mouse_position_;
+  gfx::Point last_unlocked_mouse_position_;
   // Relative to the upper-left corner of the screen.
-  gfx::Point last_global_mouse_position_;
+  gfx::Point last_unlocked_global_mouse_position_;
+  // Valid while the mouse is locked.
+  gfx::Point last_locked_global_mouse_position_;
+
+  // When the mouse cursor is moved to the center of the view by
+  // MoveCursorToCenterIfNecessary(), we ignore the resulting WM_MOUSEMOVE
+  // message.
+  bool ignore_move_to_center_message_;
 
   // 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_;
 
   ui::Range composition_range_;
 
   // Set to true if the next lbutton down message is to be ignored. Set by the
   // WM_POINTERXX handler. We do this to ensure that we don't send out
   // duplicate lbutton down messages to the renderer.
   bool ignore_next_lbutton_message_at_same_location;
   // The location of the last WM_POINTERDOWN message. We ignore the subsequent
   // lbutton down only if the locations match.
   LPARAM last_pointer_down_location_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewWin);
 };
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_WIN_H_