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

content/browser/renderer_host/render_widget_host_view_win.cc

Index: content/browser/renderer_host/render_widget_host_view_win.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_win.cc b/content/browser/renderer_host/render_widget_host_view_win.cc
index 22d4f49432b802fd67d3f1ffbf826279730c28a6..855aa5d9ffc5ee5d4b5fb05de882b0b18a6d8254 100644
--- a/content/browser/renderer_host/render_widget_host_view_win.cc
+++ b/content/browser/renderer_host/render_widget_host_view_win.cc
@@ -243,7 +243,12 @@ RenderWidgetHostViewWin::RenderWidgetHostViewWin(RenderWidgetHost* widget)
       is_loading_(false),
       overlay_color_(0),
       text_input_type_(ui::TEXT_INPUT_TYPE_NONE),
-      is_fullscreen_(false) {
+      is_fullscreen_(false),
+      last_x_(0),
+      last_y_(0),
+      last_global_x_(0),
+      last_global_y_(0),
+      ignore_mouse_movement_(true) {
   render_widget_host_->SetView(this);
   registrar_.Add(this,
                  content::NOTIFICATION_RENDERER_PROCESS_TERMINATED,
@@ -251,6 +256,7 @@ RenderWidgetHostViewWin::RenderWidgetHostViewWin(RenderWidgetHost* widget)
 }
 
 RenderWidgetHostViewWin::~RenderWidgetHostViewWin() {
+  UnlockMouse();
   ResetTooltip();
 }
 
@@ -1229,6 +1235,16 @@ LRESULT RenderWidgetHostViewWin::OnMouseEvent(UINT message, WPARAM wparam,
                                               LPARAM lparam, BOOL& handled) {
   handled = TRUE;
 
+  if (message == WM_MOUSELEAVE)
+    ignore_mouse_movement_ = true;
+
+  if (mouse_locked_) {
+    HandleLockedMouseEvent(message, wparam, lparam);
+    MoveCursorToCenter();
+    return 0;
+  }
+
+  // TODO(yzshen): is this correct? Nothing goes to the tool tip window?
   if (::IsWindow(tooltip_hwnd_)) {
     // Forward mouse events through to the tooltip window
     MSG msg;
@@ -1292,10 +1308,12 @@ LRESULT RenderWidgetHostViewWin::OnKeyEvent(UINT message, WPARAM wparam,
   handled = TRUE;
 
   // Force fullscreen windows to close on Escape.
-  if (is_fullscreen_ && (message == WM_KEYDOWN || message == WM_KEYUP) &&
-      wparam == VK_ESCAPE) {
-    SendMessage(WM_CANCELMODE);
-    return 0;
+  if ((message == WM_KEYDOWN || message == WM_KEYUP) && wparam == VK_ESCAPE) {
+    if (mouse_locked_)
+      UnlockMouse();
+    if (is_fullscreen_)
+      SendMessage(WM_CANCELMODE);
+   return 0;
   }
 
   // If we are a pop-up, forward tab related messages to our parent HWND, so
@@ -1480,6 +1498,45 @@ void RenderWidgetHostViewWin::OnAccessibilityNotifications(
   browser_accessibility_manager_->OnAccessibilityNotifications(params);
 }
 
+bool RenderWidgetHostViewWin::LockMouse() {
+  if (mouse_locked_)
+    return true;
+
+  mouse_locked_ = true;
+  // TODO(yzshen): (1) Make sure it works with the current_cursor_.
+  //               (2) if not confined successful, we can tell once we receive
+  //               mouse leave message, does that help?
+  //               (3) ResetTooltip / EnsureTooltip, and make sure they work
+  //               consistently with other part of the code.
+
+  // TODO(yzshen): Show an invisible cursor instead of using
+  // ::ShowCursor(FALSE), so that MoveCursorToCenter() works with Remote
+  // Desktop.
+  ::ShowCursor(FALSE);
+
+  MoveCursorToCenter();
+
+  CRect rect;
+  GetWindowRect(&rect);
+  ::ClipCursor(&rect);
+
+  return true;
+}
+
+void RenderWidgetHostViewWin::UnlockMouse() {
+  if (!mouse_locked_)
+    return;
+
+  mouse_locked_ = false;
+
+  ::ClipCursor(NULL);
+  ::SetCursorPos(last_global_x_, last_global_y_);
+  ::ShowCursor(TRUE);
+
+  if (render_widget_host_)
+    render_widget_host_->LostMouseLock();
+}
+
 void RenderWidgetHostViewWin::Observe(int type,
                                       const NotificationSource& source,
                                       const NotificationDetails& details) {
@@ -1800,6 +1857,33 @@ void RenderWidgetHostViewWin::ForwardMouseEventToRenderer(UINT message,
   WebMouseEvent event(
       WebInputEventFactory::mouseEvent(m_hWnd, message, wparam, lparam));
 
+  if (mouse_locked_) {
+    CPoint center = GetClientCenter();
+
+    event.movementX = event.windowX - center.x;
+    event.movementY = event.windowY - center.y;
+    event.x = last_x_;
+    event.y = last_y_;
+    event.windowX = last_x_;
+    event.windowY = last_y_;
+    event.globalX = last_global_x_;
+    event.globalY = last_global_y_;
+  } else {
+    if (ignore_mouse_movement_) {
+      ignore_mouse_movement_ = false;
+      event.movementX = 0;
+      event.movementY = 0;
+    } else {
+      event.movementX = event.globalX - last_global_x_;
+      event.movementY = event.globalY - last_global_y_;
+    }
+
+    last_x_ = event.windowX;
+    last_y_ = event.windowY;
+    last_global_x_ = event.globalX;
+    last_global_y_ = event.globalY;
+  }
+
   // Send the event to the renderer before changing mouse capture, so that the
   // capturelost event arrives after mouseup.
   render_widget_host_->ForwardMouseEvent(event);
@@ -1827,6 +1911,7 @@ void RenderWidgetHostViewWin::ForwardMouseEventToRenderer(UINT message,
     // WM_LBUTTONDOWN.
     SetFocus();
   }
+
 }
 
 void RenderWidgetHostViewWin::ShutdownHost() {
@@ -1848,3 +1933,32 @@ void RenderWidgetHostViewWin::DoPopupOrFullscreenInit(HWND parent_hwnd,
   EnsureTooltip();
   ShowWindow(IsActivatable() ? SW_SHOW : SW_SHOWNA);
 }
+
+CPoint RenderWidgetHostViewWin::GetClientCenter() const {
+  CRect rect;
+  GetClientRect(&rect);
+  return rect.CenterPoint();
+}
+
+void RenderWidgetHostViewWin::MoveCursorToCenter() const {
+  CPoint center = GetClientCenter();
+  ClientToScreen(&center);
+  if (!::SetCursorPos(center.x, center.y))
+    LOG_GETLASTERROR(WARNING) << "Failed to set cursor position.";
+}
+
+void RenderWidgetHostViewWin::HandleLockedMouseEvent(UINT message,
+                                                     WPARAM wparam,
+                                                     LPARAM lparam) {
+  DCHECK(mouse_locked_);
+
+  if (message == WM_MOUSEMOVE) {
+    CPoint center = GetClientCenter();
+    // Ignore WM_MOUSEMOVE messages generated by MoveCursorToCenter().
+    if (LOWORD(lparam) == center.x && HIWORD(lparam) == center.y)
+      return;
+  }
+
+  ForwardMouseEventToRenderer(message, wparam, lparam);
+}
+