Commit 34d673af authored by Chris Lord's avatar Chris Lord
Browse files

Bug 753742 - Force layer build on scroll frames with a displayport. r=tn 

Force building layers for all scroll frames that have a displayport set.
This fixes gfx/layers/ipc/CompositorParent mistakenly using FrameMetrics from
incorrect frames, due to the root scroll frame not having a layer.
parent fe4f9334

layout/generic/nsGfxScrollFrame.cpp

+16 −11
Original line number Diff line number Diff line
@@ -2302,17 +2302,22 @@ nsGfxScrollFrameInner::BuildDisplayList(nsDisplayListBuilder* aBuilder, 
  NS_ENSURE_SUCCESS(rv, rv);



  // Since making new layers is expensive, only use nsDisplayScrollLayer

  // if the area is scrollable and there's a displayport (or we're the content

  // process).

  // if the area is scrollable and we're the content process.

  // When a displayport is being used, force building of a layer so that

  // CompositorParent can always find the scrollable layer for the root content

  // document.

  if (usingDisplayport) {

    mShouldBuildLayer = true;

  } else {

    nsRect scrollRange = GetScrollRange();

    ScrollbarStyles styles = GetScrollbarStylesFromFrame();

    mShouldBuildLayer =

       (styles.mHorizontal != NS_STYLE_OVERFLOW_HIDDEN ||

        styles.mVertical != NS_STYLE_OVERFLOW_HIDDEN) &&

     (usingDisplayport ||

       (XRE_GetProcessType() == GeckoProcessType_Content &&

        (scrollRange.width > 0 || scrollRange.height > 0) &&

       (!mIsRoot || !mOuter->PresContext()->IsRootContentDocument())));

        (!mIsRoot || !mOuter->PresContext()->IsRootContentDocument()));

  }



  nsRect clip;

  nscoord radii[8];