Bug 1186662 - Part 3: Suppress the Displayport during active resize on Windows. r=kats,jimm

--HG--
extra : commitid : FI8OCMTZVoP
extra : rebase_source : f09763a2f182039f7cddc7eda32ec4a7cc6b76ff

widget/windows/nsWindow.cpp

@@ -337,7 +337,9 @@ static bool gIsPointerEventsEnabled = false;
  *
  **************************************************************/
 
-nsWindow::nsWindow() : nsWindowBase()
+nsWindow::nsWindow()
+  : nsWindowBase()
+  , mResizeState(NOT_RESIZING)
 {
   mIconSmall            = nullptr;
   mIconBig              = nullptr;
@@ -5325,11 +5327,49 @@ nsWindow::ProcessMessage(UINT msg, WPARAM& wParam, LPARAM& lParam,
       DispatchPendingEvents();
       break;
 
+    case WM_SIZING:
+    {
+      // When we get WM_ENTERSIZEMOVE we don't know yet if we're in a live
+      // resize or move event. Instead we wait for first VM_SIZING message
+      // within a ENTERSIZEMOVE to consider this a live resize event.
+      if (mResizeState == IN_SIZEMOVE) {
+        mResizeState = RESIZING;
+        nsCOMPtr<nsIObserverService> observerService =
+          mozilla::services::GetObserverService();
+
+        if (observerService) {
+          observerService->NotifyObservers(nullptr, "live-resize-start",
+                                           nullptr);
+        }
+      }
+      break;
+    }
+
+    case WM_ENTERSIZEMOVE:
+    {
+      if (mResizeState == NOT_RESIZING) {
+        mResizeState = IN_SIZEMOVE;
+      }
+      break;
+    }
+
     case WM_EXITSIZEMOVE:
+    {
+      if (mResizeState == RESIZING) {
+        mResizeState = NOT_RESIZING;
+        nsCOMPtr<nsIObserverService> observerService = mozilla::services::GetObserverService();
+
+        if (observerService) {
+          observerService->NotifyObservers(nullptr, "live-resize-end", nullptr);
+        }
+      }
+
       if (!sIsInMouseCapture) {
         NotifySizeMoveDone();
       }
+
       break;
+    }
 
     case WM_NCLBUTTONDBLCLK:
       DispatchMouseEvent(NS_MOUSE_DOUBLECLICK, 0, lParamToClient(lParam),
@@ -7521,7 +7561,6 @@ nsWindow::DealWithPopups(HWND aWnd, UINT aMessage,
       return false;
 
     case WM_MOVING:
-    case WM_SIZING:
     case WM_MENUSELECT:
       break;
 

widget/windows/nsWindow.h

@@ -562,6 +562,14 @@ protected:
 
   nsIntRect             mLastPaintBounds;
 
+  // Used for displayport suppression during window resize
+  enum ResizeState {
+    NOT_RESIZING,
+    IN_SIZEMOVE,
+    RESIZING,
+  };
+  ResizeState mResizeState;
+
   // Transparency
 #ifdef MOZ_XUL
   // Use layered windows to support full 256 level alpha translucency