Bug 695275 - Add nsIDOMWindowUtils::CheckAndClearPaintedState to test painting. r=roc

dom/base/nsDOMWindowUtils.cpp

@@ -1941,3 +1941,20 @@ nsDOMWindowUtils::GetMayHaveTouchEventListeners(bool* aResult)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsDOMWindowUtils::CheckAndClearPaintedState(nsIDOMElement* aElement, bool* aResult)
+{
+  if (!aElement) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsresult rv;
+  nsCOMPtr<nsIContent> content = do_QueryInterface(aElement, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsIFrame* frame = content->GetPrimaryFrame();
+
+  *aResult = frame->CheckAndClearPaintedState();
+  return NS_OK;
+}
+

dom/interfaces/base/nsIDOMWindowUtils.idl

@@ -68,7 +68,7 @@ interface nsIDOMWindow;
 interface nsIDOMFile;
 interface nsIFile;
 
-[scriptable, uuid(bc6c156a-c41f-43dd-ace3-e3bca9894ed1)]
+[scriptable, uuid(910484d7-219c-4c72-b999-7a7e9c954646)]
 interface nsIDOMWindowUtils : nsISupports {
 
   /**
@@ -919,4 +919,11 @@ interface nsIDOMWindowUtils : nsISupports {
    * true if the (current inner) window may have event listeners for touch events.
    */
   readonly attribute boolean mayHaveTouchEventListeners;
+ 
+  /**
+   * Check if any ThebesLayer painting has been done for this element,
+   * clears the painted flags if they have.
+   */
+  boolean checkAndClearPaintedState(in nsIDOMElement aElement);
+
 };

layout/base/FrameLayerBuilder.cpp

@@ -2106,6 +2106,10 @@ FrameLayerBuilder::DrawThebesLayer(ThebesLayer* aLayer,
     if (cdi->mInactiveLayer) {
       PaintInactiveLayer(builder, cdi->mItem, aContext);
     } else {
+      nsIFrame* frame = cdi->mItem->GetUnderlyingFrame();
+      if (frame) {
+        frame->AddStateBits(NS_FRAME_PAINTED_THEBES);
+      }
       cdi->mItem->Paint(builder, rc);
     }
 

layout/generic/nsFrame.cpp

@@ -282,6 +282,25 @@ nsIFrame::MarkAsAbsoluteContainingBlock() {
   Properties().Set(AbsoluteContainingBlockProperty(), new nsAbsoluteContainingBlock(GetAbsoluteListID()));
 }
 
+bool
+nsIFrame::CheckAndClearPaintedState()
+{
+  bool result = (GetStateBits() & NS_FRAME_PAINTED_THEBES);
+  RemoveStateBits(NS_FRAME_PAINTED_THEBES);
+  
+  nsIFrame::ChildListIterator lists(this);
+  for (; !lists.IsDone(); lists.Next()) {
+    nsFrameList::Enumerator childFrames(lists.CurrentList());
+    for (; !childFrames.AtEnd(); childFrames.Next()) {
+      nsIFrame* child = childFrames.get();
+      if (child->CheckAndClearPaintedState()) {
+        result = true;
+      }
+    }
+  }
+  return result;
+}
+
 static bool ApplyOverflowClipping(nsDisplayListBuilder* aBuilder,
                                     const nsIFrame* aFrame,
                                     const nsStyleDisplay* aDisp, 

layout/generic/nsIFrame.h

@@ -290,6 +290,9 @@ typedef PRUint64 nsFrameState;
 // Frame can accept absolutely positioned children.
 #define NS_FRAME_HAS_ABSPOS_CHILDREN                NS_FRAME_STATE_BIT(37)
 
+// A display item for this frame has been painted as part of a ThebesLayer.
+#define NS_FRAME_PAINTED_THEBES                     NS_FRAME_STATE_BIT(38)
+
 // The lower 20 bits and upper 32 bits of the frame state are reserved
 // by this API.
 #define NS_FRAME_RESERVED                           ~NS_FRAME_IMPL_RESERVED
@@ -2753,6 +2756,10 @@ NS_PTR_TO_INT32(frame->Properties().Get(nsIFrame::EmbeddingLevelProperty()))
   // Child frame types override this function to select their own child list name
   virtual mozilla::layout::FrameChildListID GetAbsoluteListID() const { return kAbsoluteList; }
 
+  // Checks if we (or any of our descendents) have NS_FRAME_PAINTED_THEBES set, and
+  // clears this bit if so.
+  bool CheckAndClearPaintedState();
+
 protected:
   // Members
   nsRect           mRect;