Bug 899745. Remove top most z-index tracking from views because it is unused. r=mats

layout/generic/nsContainerFrame.cpp

@@ -820,7 +820,7 @@ nsContainerFrame::SyncFrameViewProperties(nsPresContext*  aPresContext,
     }
   }
 
-  vm->SetViewZIndex(aView, autoZIndex, zIndex, isPositioned);
+  vm->SetViewZIndex(aView, autoZIndex, zIndex);
 }
 
 static nscoord GetCoord(const nsStyleCoord& aCoord, nscoord aIfNotCoord)

view/public/nsView.h

@@ -35,11 +35,6 @@ enum nsViewVisibility {
 // Indicates that the view is a floating view.
 #define NS_VIEW_FLAG_FLOATING             0x0008
 
-// If set it indicates that this view should be
-// displayed above z-index:auto views if this view 
-// is z-index:auto also
-#define NS_VIEW_FLAG_TOPMOST              0x0010
-
 //----------------------------------------------------------------------
 
 /**
@@ -344,7 +339,7 @@ public:
    * relative to the view's siblings.
    * @param zindex new z depth
    */
-  void SetZIndex(bool aAuto, int32_t aZIndex, bool aTopMost);
+  void SetZIndex(bool aAuto, int32_t aZIndex);
   bool GetZIndexIsAuto() const { return (mVFlags & NS_VIEW_FLAG_AUTO_ZINDEX) != 0; }
   int32_t GetZIndex() const { return mZIndex; }
 
@@ -435,9 +430,6 @@ private:
   void InsertChild(nsView *aChild, nsView *aSibling);
   void RemoveChild(nsView *aChild);
 
-  void SetTopMost(bool aTopMost) { aTopMost ? mVFlags |= NS_VIEW_FLAG_TOPMOST : mVFlags &= ~NS_VIEW_FLAG_TOPMOST; }
-  bool IsTopMost() { return((mVFlags & NS_VIEW_FLAG_TOPMOST) != 0); }
-
   void ResetWidgetBounds(bool aRecurse, bool aForceSync);
   void AssertNoWindow();
 

view/public/nsViewManager.h

@@ -203,12 +203,8 @@ public:
    * relative to the view's siblings.
    * @param aView view to change z depth of
    * @param aZindex explicit z depth
-   * @param aTopMost used when this view is z-index:auto to compare against 
-   *        other z-index:auto views.
-   *        true if the view should be topmost when compared with 
-   *        other z-index:auto views.
    */
-  void SetViewZIndex(nsView *aView, bool aAutoZIndex, int32_t aZindex, bool aTopMost = false);
+  void SetViewZIndex(nsView *aView, bool aAutoZIndex, int32_t aZindex);
 
   /**
    * Set whether the view "floats" above all other views,

view/src/nsView.cpp

@@ -735,12 +735,11 @@ nsresult nsView::DetachFromTopLevelWidget()
   return NS_OK;
 }
 
-void nsView::SetZIndex(bool aAuto, int32_t aZIndex, bool aTopMost)
+void nsView::SetZIndex(bool aAuto, int32_t aZIndex)
 {
   bool oldIsAuto = GetZIndexIsAuto();
   mVFlags = (mVFlags & ~NS_VIEW_FLAG_AUTO_ZINDEX) | (aAuto ? NS_VIEW_FLAG_AUTO_ZINDEX : 0);
   mZIndex = aZIndex;
-  SetTopMost(aTopMost);
   
   if (HasWidget() || !oldIsAuto || !aAuto) {
     UpdateNativeWidgetZIndexes(this, FindNonAutoZIndex(this));

view/src/nsViewManager.cpp

@@ -160,7 +160,7 @@ nsViewManager::SetRootView(nsView *aView)
       InvalidateHierarchy();
     }
 
-    mRootView->SetZIndex(false, 0, false);
+    mRootView->SetZIndex(false, 0);
   }
   // Else don't touch mRootViewManager
 }
@@ -862,7 +862,7 @@ nsViewManager::InsertChild(nsView *aParent, nsView *aChild, int32_t aZIndex)
 {
   // no-one really calls this with anything other than aZIndex == 0 on a fresh view
   // XXX this method should simply be eliminated and its callers redirected to the real method
-  SetViewZIndex(aChild, false, aZIndex, false);
+  SetViewZIndex(aChild, false, aZIndex);
   InsertChild(aParent, aChild, nullptr, true);
 }
 
@@ -941,7 +941,7 @@ bool nsViewManager::IsViewInserted(nsView *aView)
 }
 
 void
-nsViewManager::SetViewZIndex(nsView *aView, bool aAutoZIndex, int32_t aZIndex, bool aTopMost)
+nsViewManager::SetViewZIndex(nsView *aView, bool aAutoZIndex, int32_t aZIndex)
 {
   NS_ASSERTION((aView != nullptr), "no view");
 
@@ -955,7 +955,7 @@ nsViewManager::SetViewZIndex(nsView *aView, bool aAutoZIndex, int32_t aZIndex, b
     aZIndex = 0;
   }
 
-  aView->SetZIndex(aAutoZIndex, aZIndex, aTopMost);
+  aView->SetZIndex(aAutoZIndex, aZIndex);
 }
 
 nsViewManager*