Bug 556432 - Dragging a content selection shows non-selectable text in the drag feedback. r=roc

layout/base/nsDisplayList.cpp

@@ -75,7 +75,7 @@ nsDisplayListBuilder::nsDisplayListBuilder(nsIFrame* aReferenceFrame,
       mBuildCaret(aBuildCaret),
       mEventDelivery(aIsForEvents),
       mIsAtRootOfPseudoStackingContext(PR_FALSE),
-      mPaintAllFrames(PR_FALSE),
+      mSelectedFramesOnly(PR_FALSE),
       mAccurateVisibleRegions(PR_FALSE),
       mInTransform(PR_FALSE),
       mSyncDecodeImages(PR_FALSE),

layout/base/nsDisplayList.h

@@ -235,11 +235,14 @@ public:
    */
   nsIFrame* GetIgnoreScrollFrame() { return mIgnoreScrollFrame; }
   /**
-   * Calling this setter makes us ignore all dirty rects and include all
-   * descendant frames in the display list, wherever they may be positioned.
+   * Calling this setter makes us:
+   * 1. include all positioned descendant frames in the display list,
+   *    wherever they may be positioned (even outside the dirty rects).
+   * 2. exclude all leaf frames that does not have the NS_FRAME_SELECTED_CONTENT
+   *    bit.
    */
-  void SetPaintAllFrames() { mPaintAllFrames = PR_TRUE; }
-  PRBool GetPaintAllFrames() { return mPaintAllFrames; }
+  void SetSelectedFramesOnly() { mSelectedFramesOnly = PR_TRUE; }
+  PRBool GetSelectedFramesOnly() { return mSelectedFramesOnly; }
   /**
    * Calling this setter makes us compute accurate visible regions at the cost
    * of performance if regions get very complex.
@@ -426,7 +429,7 @@ private:
   PRPackedBool                   mEventDelivery;
   PRPackedBool                   mIsBackgroundOnly;
   PRPackedBool                   mIsAtRootOfPseudoStackingContext;
-  PRPackedBool                   mPaintAllFrames;
+  PRPackedBool                   mSelectedFramesOnly;
   PRPackedBool                   mAccurateVisibleRegions;
   // True when we're building a display list that's directly or indirectly
   // under an nsDisplayTransform

layout/base/nsPresShell.cpp

@@ -1023,7 +1023,8 @@ protected:
   // create a RangePaintInfo for the range aRange containing the
   // display list needed to paint the range to a surface
   RangePaintInfo* CreateRangePaintInfo(nsIDOMRange* aRange,
-                                       nsRect& aSurfaceRect);
+                                       nsRect& aSurfaceRect,
+                                       PRBool aForPrimarySelection);
 
   /*
    * Paint the items to a new surface and return it.
@@ -5458,7 +5459,8 @@ static PRBool gDumpRangePaintList = PR_FALSE;
 
 RangePaintInfo*
 PresShell::CreateRangePaintInfo(nsIDOMRange* aRange,
-                                nsRect& aSurfaceRect)
+                                nsRect& aSurfaceRect,
+                                PRBool aForPrimarySelection)
 {
   NS_TIME_FUNCTION_WITH_DOCURL;
 
@@ -5507,7 +5509,9 @@ PresShell::CreateRangePaintInfo(nsIDOMRange* aRange,
   nsRect ancestorRect = ancestorFrame->GetOverflowRect();
 
   // get a display list containing the range
-  info->mBuilder.SetPaintAllFrames();
+  if (aForPrimarySelection) {
+    info->mBuilder.SetSelectedFramesOnly();
+  }
   info->mBuilder.EnterPresShell(ancestorFrame, ancestorRect);
   ancestorFrame->BuildDisplayListForStackingContext(&info->mBuilder,
                                                     ancestorRect, &info->mList);
@@ -5685,7 +5689,7 @@ PresShell::RenderNode(nsIDOMNode* aNode,
   if (NS_FAILED(range->SelectNode(aNode)))
     return nsnull;
 
-  RangePaintInfo* info = CreateRangePaintInfo(range, area);
+  RangePaintInfo* info = CreateRangePaintInfo(range, area, PR_FALSE);
   if (info && !rangeItems.AppendElement(info)) {
     delete info;
     return nsnull;
@@ -5733,7 +5737,7 @@ PresShell::RenderSelection(nsISelection* aSelection,
     nsCOMPtr<nsIDOMRange> range;
     aSelection->GetRangeAt(r, getter_AddRefs(range));
 
-    RangePaintInfo* info = CreateRangePaintInfo(range, area);
+    RangePaintInfo* info = CreateRangePaintInfo(range, area, PR_TRUE);
     if (info && !rangeItems.AppendElement(info)) {
       delete info;
       return nsnull;

layout/generic/nsFrame.cpp

@@ -1467,9 +1467,14 @@ nsIFrame::BuildDisplayListForChild(nsDisplayListBuilder*   aBuilder,
       dirty.Empty();
     }
     pseudoStackingContext = PR_TRUE;
+  } else if (aBuilder->GetSelectedFramesOnly() &&
+             aChild->IsLeaf() &&
+             !(aChild->GetStateBits() & NS_FRAME_SELECTED_CONTENT)) {
+    return NS_OK;
   }
 
-  if (aBuilder->GetPaintAllFrames()) {
+  if (aBuilder->GetSelectedFramesOnly() &&
+      (aChild->GetStateBits() & NS_FRAME_OUT_OF_FLOW)) {
     dirty = aChild->GetOverflowRect();
   } else if (!(aChild->GetStateBits() & NS_FRAME_FORCE_DISPLAY_LIST_DESCEND_INTO)) {
     // No need to descend into aChild to catch placeholders for visible