1 files changed, 36 insertions, 2 deletions
diff --git a/ui/views/win/hwnd_message_handler.cc b/ui/views/win/hwnd_message_handler.cc
index 92c8512..90140ed 100644
--- a/ui/views/win/hwnd_message_handler.cc
+++ b/ui/views/win/hwnd_message_handler.cc
@@ -256,6 +256,13 @@ void AddScrollStylesToWindow(HWND window) {
 
 const int kTouchDownContextResetTimeout = 500;
 
+// Windows does not flag synthesized mouse messages from touch in all cases.
+// This causes us grief as we don't want to process touch and mouse messages
+// concurrently. Hack as per msdn is to check if the time difference between
+// the touch message and the mouse move is within 500 ms and at the same
+// location as the cursor.
+const int kSynthesizedMouseTouchMessagesTimeDifference = 500;
+
 }  // namespace
 
 // A scoping class that prevents a window from being able to redraw in response
@@ -325,6 +332,8 @@ class HWNDMessageHandler::ScopedRedrawLock {
 ////////////////////////////////////////////////////////////////////////////////
 // HWNDMessageHandler, public:
 
+long HWNDMessageHandler::last_touch_message_time_ = 0;
+
 HWNDMessageHandler::HWNDMessageHandler(HWNDMessageHandlerDelegate* delegate)
     : delegate_(delegate),
       fullscreen_handler_(new FullscreenHandler),
@@ -2116,6 +2125,8 @@ LRESULT HWNDMessageHandler::OnTouchEvent(UINT message,
 
       ScreenToClient(hwnd(), &point);
 
+      last_touch_message_time_ = ::GetMessageTime();
+
       ui::EventType touch_event_type = ui::ET_UNKNOWN;
 
       if (input[i].dwFlags & TOUCHEVENTF_DOWN) {
@@ -2332,10 +2343,11 @@ LRESULT HWNDMessageHandler::HandleMouseEventInternal(UINT message,
     // be WM_RBUTTONUP instead of WM_NCRBUTTONUP.
     SetCapture();
   }
-  MSG msg = { hwnd(), message, w_param, l_param, GetMessageTime(),
+  long message_time = GetMessageTime();
+  MSG msg = { hwnd(), message, w_param, l_param, message_time,
               { CR_GET_X_LPARAM(l_param), CR_GET_Y_LPARAM(l_param) } };
   ui::MouseEvent event(msg);
-  if (!touch_ids_.empty() || ui::IsMouseEventFromTouch(message))
+  if (IsSynthesizedMouseMessage(message, message_time, l_param))
     event.set_flags(event.flags() | ui::EF_FROM_TOUCH);
 
   if (!(event.flags() & ui::EF_IS_NON_CLIENT))
@@ -2379,4 +2391,26 @@ LRESULT HWNDMessageHandler::HandleMouseEventInternal(UINT message,
   return 0;
 }
 
+bool HWNDMessageHandler::IsSynthesizedMouseMessage(unsigned int message,
+                                                   int message_time,
+                                                   LPARAM l_param) {
+  if (ui::IsMouseEventFromTouch(message))
+    return true;
+  // Ignore mouse messages which occur at the same location as the current
+  // cursor position and within a time difference of 500 ms from the last
+  // touch message.
+  if (last_touch_message_time_ && message_time >= last_touch_message_time_ &&
+      ((message_time - last_touch_message_time_) <=
+          kSynthesizedMouseTouchMessagesTimeDifference)) {
+    POINT mouse_location = CR_POINT_INITIALIZER_FROM_LPARAM(l_param);
+    ::ClientToScreen(hwnd(), &mouse_location);
+    POINT cursor_pos = {0};
+    ::GetCursorPos(&cursor_pos);
+    if (memcmp(&cursor_pos, &mouse_location, sizeof(POINT)))
+      return false;
+    return true;
+  }
+  return false;
+}
+
 }  // namespace views