Bug 672175 part.8 Compute modifier key state in MouseScrollHandler r=jimm

widget/windows/WinMouseScrollHandler.cpp

@@ -167,6 +167,20 @@ MouseScrollHandler::DispatchEvent(nsWindow* aWindow, nsGUIEvent& aEvent)
   return aWindow->DispatchWindowEvent(&aEvent);
 }
 
+/* static */
+nsModifierKeyState
+MouseScrollHandler::GetModifierKeyState()
+{
+  nsModifierKeyState result;
+  // Assume the Control key is down if the Elantech touchpad has sent the
+  // mis-ordered WM_KEYDOWN/WM_MOUSEWHEEL messages.  (See the comment in
+  // MouseScrollHandler::Device::Elantech::HandleKeyMessage().)
+  if (!result.mIsControlDown) {
+    result.mIsControlDown = Device::Elantech::IsZooming();
+  }
+  return result;
+}
+
 /******************************************************************************
  *
  * EventInfo

widget/windows/WinMouseScrollHandler.h

@@ -15,6 +15,7 @@
 
 class nsWindow;
 class nsGUIEvent;
+struct nsModifierKeyState;
 
 namespace mozilla {
 namespace widget {
@@ -33,6 +34,13 @@ public:
                              LRESULT *aRetValue,
                              bool &aEatMessage);
 
+  /**
+   * GetModifierKeyState() returns current modifier key state.
+   * Note that some devices need some hack for the modifier key state.
+   * This method does it automatically.
+   */
+  static nsModifierKeyState GetModifierKeyState();
+
 private:
   MouseScrollHandler();
   ~MouseScrollHandler();

widget/windows/nsWindow.cpp

@@ -6295,21 +6295,13 @@ nsWindow::OnMouseWheelInternal(UINT aMessage, WPARAM aWParam, LPARAM aLParam,
   // means we process this message
   *aRetValue = eventInfo.ComputeMessageResult(true);
 
-  nsModifierKeyState modKeyState;
+  nsModifierKeyState modKeyState = MouseScrollHandler::GetModifierKeyState();
 
   // Our positive delta value means to bottom or right.
   // But positive native delta value means to top or right.
   // Use orienter for computing our delta value with native delta value.
   PRInt32 orienter = eventInfo.IsVertical() ? -1 : 1;
 
-  // Assume the Control key is down if the Elantech touchpad has sent the
-  // mis-ordered WM_KEYDOWN/WM_MOUSEWHEEL messages.  (See the comment in
-  // MouseScrollHandler::Device::Elantech::HandleKeyMessage().)
-  if (!modKeyState.mIsControlDown) {
-    modKeyState.mIsControlDown =
-      MouseScrollHandler::Device::Elantech::IsZooming();
-  }
-
   // Create line (or page) scroll event.
   nsMouseScrollEvent scrollEvent(true, NS_MOUSE_SCROLL, this);