Don't track mouse events in HWNDMessageHandler when they are forwarded by the LegacyRenderWidgetHost

ui/views/win/hwnd_message_handler.cc

 // Copyright (c) 2012 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.
 
 #include "ui/views/win/hwnd_message_handler.h"
 
 #include <dwmapi.h>
 #include <oleacc.h>
 #include <shellapi.h>
 #include <wtsapi32.h>
@@ skipping 1004 matching lines @@
 
   bool active = activation_state != WA_INACTIVE && !minimized;
   if (delegate_->CanActivate())
     delegate_->HandleActivationChanged(active);
 
   if (!active) {
     // We might get activated/inactivated without being enabled, so we need to
     // clear restore_focus_when_enabled_.
     restore_focus_when_enabled_ = false;
     delegate_->SaveFocusOnDeactivate();
+    // When we lose activation send a dummy WM_MOUSELEAVE message. This is to
+    // handle cases when we don't track certain WM_MOUSEMOVE messages like those
+    // coming from a child.
+    ::PostMessage(hwnd(), WM_MOUSELEAVE, 0, 0);

[sky, 2014/02/12 22:51:29]

If the legacy hwnd starts tracking mouse events, is this necessary any longer?

[ananta, 2014/02/12 23:17:08]

When it does. The TrackMouseEvent API succeeds on the legacy hwnd, but fails to
track the mouse. Until then this is necessary.

   } else {
     // We must restore the focus after the message has been DefProc'ed as it
     // does set the focus to the last focused HWND.
     // Note that if the window is not enabled, we cannot restore the focus as
     // calling ::SetFocus on a child of the non-enabled top-window would fail.
     // This is the case when showing a modal dialog (such as 'open file',
     // 'print'...) from a different thread.
     // In that case we delay the focus restoration to when the window is enabled
     // again.
     if (!IsWindowEnabled(hwnd())) {
@@ skipping 586 matching lines @@
       }
     }
   } else if (message == WM_NCRBUTTONDOWN &&
       (w_param == HTCAPTION || w_param == HTSYSMENU)) {
     is_right_mouse_pressed_on_caption_ = true;
     // We SetCapture() to ensure we only show the menu when the button
     // down and up are both on the caption. Note: this causes the button up to
     // be WM_RBUTTONUP instead of WM_NCRBUTTONUP.
     SetCapture();
   }
-
   MSG msg = { hwnd(), message, w_param, l_param, GetMessageTime(),
               { CR_GET_X_LPARAM(l_param), CR_GET_Y_LPARAM(l_param) } };
   ui::MouseEvent event(msg);
   if (!touch_ids_.empty() || ui::IsMouseEventFromTouch(message))
     event.set_flags(event.flags() | ui::EF_FROM_TOUCH);
 
   if (!(event.flags() & ui::EF_IS_NON_CLIENT))
     delegate_->HandleTooltipMouseMove(message, w_param, l_param);
 
-  if (event.type() == ui::ET_MOUSE_MOVED && !HasCapture()) {
+  if (event.type() == ui::ET_MOUSE_MOVED && !HasCapture() &&
+      HIWORD(w_param) != SPECIAL_MOUSEMOVE_NOT_TO_BE_TRACKED) {

[sky, 2014/02/12 22:51:29]

Does this imply we need to track mouse mouse events in the child? If we don't,
doesn't that mean we may miss an exit?

[ananta, 2014/02/12 23:17:08]

When the mouse leaves the bounds of the child we would get a WM_NCMOUSEMOVE or a
WM_MOUSEMOVE depending on where we would go. That should get us a WM_MOUSELEAVE.
Additionally if we lose activation we have a dummy WM_MOUSELEAVE posted to cover
for this.

     // Windows only fires WM_MOUSELEAVE events if the application begins
     // "tracking" mouse events for a given HWND during WM_MOUSEMOVE events.
     // We need to call |TrackMouseEvents| to listen for WM_MOUSELEAVE.
     TrackMouseEvents((message == WM_NCMOUSEMOVE) ?
         TME_NONCLIENT | TME_LEAVE : TME_LEAVE);
   } else if (event.type() == ui::ET_MOUSE_EXITED) {
     // Reset our tracking flags so future mouse movement over this
     // NativeWidgetWin results in a new tracking session. Fall through for
     // OnMouseEvent.
     active_mouse_tracking_flags_ = 0;
@@ skipping 737 matching lines @@
   SetMsgHandled(FALSE);
 }
 
 void HWNDMessageHandler::HandleTouchEvents(const TouchEvents& touch_events) {
   base::WeakPtr<HWNDMessageHandler> ref(weak_factory_.GetWeakPtr());
   for (size_t i = 0; i < touch_events.size() && ref; ++i)
     delegate_->HandleTouchEvent(touch_events[i]);
 }
 
 }  // namespace views