Bug 1163113 - Implement -moz-window-dragging on Windows for Graphene. r=jimm

widget/windows/nsWindow.cpp

@@ -2673,6 +2673,23 @@ void nsWindow::UpdateOpaqueRegion(const nsIntRegion &aOpaqueRegion)
   }
 }
 
+/**************************************************************
+*
+* SECTION: nsIWidget::UpdateWindowDraggingRegion
+*
+* For setting the draggable titlebar region from CSS
+* with -moz-window-dragging: drag.
+*
+**************************************************************/
+
+void
+nsWindow::UpdateWindowDraggingRegion(const nsIntRegion& aRegion)
+{
+  if (mDraggableRegion != aRegion) {
+    mDraggableRegion = aRegion;
+  }
+}
+
 void nsWindow::UpdateGlass()
 {
   MARGINS margins = mGlassMargins;
@@ -5582,7 +5599,9 @@ nsWindow::ClientMarginHitTestPoint(int32_t mx, int32_t my)
     ::ScreenToClient(mWnd, &pt);
     if (pt.x == mCachedHitTestPoint.x && pt.y == mCachedHitTestPoint.y &&
         TimeStamp::Now() - mCachedHitTestTime < TimeDuration::FromMilliseconds(HITTEST_CACHE_LIFETIME_MS)) {
-      testResult = mCachedHitTestResult;
+      return mCachedHitTestResult;
+    } else if (mDraggableRegion.Contains(pt.x, pt.y)) {
+      testResult = HTCAPTION;
     } else {
       WidgetMouseEvent event(true, NS_MOUSE_MOZHITTEST, this,
                              WidgetMouseEvent::eReal,
@@ -5594,16 +5613,15 @@ nsWindow::ClientMarginHitTestPoint(int32_t mx, int32_t my)
       if (result) {
         // The mouse is over a blank area
         testResult = testResult == HTCLIENT ? HTCAPTION : testResult;
-
       } else {
         // There's content over the mouse pointer. Set HTCLIENT
         // to possibly override a resizer border.
         testResult = HTCLIENT;
       }
-      mCachedHitTestPoint = pt;
-      mCachedHitTestTime = TimeStamp::Now();
-      mCachedHitTestResult = testResult;
     }
+    mCachedHitTestPoint = pt;
+    mCachedHitTestTime = TimeStamp::Now();
+    mCachedHitTestResult = testResult;
   }
 
   return testResult;

widget/windows/nsWindow.h

@@ -194,6 +194,7 @@ public:
   void                    SetDrawsInTitlebar(bool aState);
   mozilla::TemporaryRef<mozilla::gfx::DrawTarget> StartRemoteDrawing() override;
   virtual void            EndRemoteDrawing() override;
+  virtual void UpdateWindowDraggingRegion(const nsIntRegion& aRegion) override;
 
   virtual void            UpdateThemeGeometries(const nsTArray<ThemeGeometry>& aThemeGeometries) override;
   virtual uint32_t        GetMaxTouchPoints() const override;
@@ -519,6 +520,9 @@ protected:
 
   nsCOMPtr<nsIIdleServiceInternal> mIdleService;
 
+  // Draggable titlebar region maintained by UpdateWindowDraggingRegion
+  nsIntRegion mDraggableRegion;
+
   // Hook Data Memebers for Dropdowns. sProcessHook Tells the
   // hook methods whether they should be processing the hook
   // messages.