Bug 1519285 - Remove FrameMetrics::mVisualViewportOffset. r=kats

It is now redundant with mScrollOffset which always stores the
visual scroll offset.

Differential Revision: https://phabricator.services.mozilla.com/D87162

gfx/layers/FrameMetrics.h

@@ -110,7 +110,6 @@ struct FrameMetrics {
         mExtraResolution(),
         mPaintRequestTime(),
         mScrollUpdateType(eNone),
-        mVisualViewportOffset(0, 0),
         mVisualScrollUpdateType(eNone),
         mIsRootContent(false),
         mIsRelative(false),
@@ -141,7 +140,6 @@ struct FrameMetrics {
            mExtraResolution == aOther.mExtraResolution &&
            mPaintRequestTime == aOther.mPaintRequestTime &&
            mScrollUpdateType == aOther.mScrollUpdateType &&
-           mVisualViewportOffset == aOther.mVisualViewportOffset &&
            mVisualScrollUpdateType == aOther.mVisualScrollUpdateType &&
            mIsRootContent == aOther.mIsRootContent &&
            mIsRelative == aOther.mIsRelative &&
@@ -531,13 +529,6 @@ struct FrameMetrics {
   }
   bool IsScrollInfoLayer() const { return mIsScrollInfoLayer; }
 
-  void SetVisualViewportOffset(const CSSPoint& aVisualViewportOffset) {
-    mVisualViewportOffset = aVisualViewportOffset;
-  }
-  const CSSPoint& GetVisualViewportOffset() const {
-    return mVisualViewportOffset;
-  }
-
   void SetVisualScrollUpdateType(ScrollOffsetUpdateType aUpdateType) {
     mVisualScrollUpdateType = aUpdateType;
   }
@@ -722,16 +713,9 @@ struct FrameMetrics {
   // if the APZC receiving this metrics should update its local copy.
   ScrollOffsetUpdateType mScrollUpdateType;
 
-  // These fields are used when the main thread wants to set a visual viewport
-  // offset that's distinct from the layout viewport offset.
-  // In this case, mVisualScrollUpdateType is set to eMainThread, and
-  // mVisualViewportOffset is set to desired visual viewport offset (relative
-  // to the document, like mScrollOffset).
-  // TODO: Get rid of mVisualViewportOffset: between mViewport.TopLeft() and
-  //       mScrollOffset, we have enough storage for the two scroll offsets.
-  //       However, to avoid confusion, that first requires refactoring
-  //       existing to consistently use the two fields for those two purposes.
-  CSSPoint mVisualViewportOffset;
+  // Theis field is set to eMainThread when the main thread wants APZ to
+  // scroll to a visual viewport offset that's distinct from the layout
+  // viewport offset.
   ScrollOffsetUpdateType mVisualScrollUpdateType;
 
   // 'fixed layer margins' on the main-thread. This is only used for the

gfx/layers/LayersLogging.cpp

@@ -224,7 +224,6 @@ void AppendToString(std::stringstream& aStream, const FrameMetrics& m,
   AppendToString(aStream, m.GetCompositionBounds(), "{ [cb=");
   AppendToString(aStream, m.GetScrollableRect(), "] [sr=");
   AppendToString(aStream, m.GetVisualScrollOffset(), "] [s=");
-  AppendToString(aStream, m.GetVisualViewportOffset(), "] [vs=");
   if (m.GetDoSmoothScroll()) {
     AppendToString(aStream, m.GetSmoothScrollOffset(), "] [ss=");
   }

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -3785,12 +3785,12 @@ LayerToParentLayerMatrix4x4 APZCTreeManager::ComputeTransformForScrollThumb(
       // viewport offset that the main thread does not (yet) know about. We want
       // asyncScrollY to be
       //   asyncScrollY = -(GetEffectiveScrollOffset -
-      //   mLastContentPaintMetrics.GetVisualViewportOffset()) * effectiveZoom
+      //   mLastContentPaintMetrics.GetVisualScrollOffset()) * effectiveZoom
       // because the main thread positions the scrollbars at the visual viewport
       // offset that it knows about. (aMetrics is mLastContentPaintMetrics)
 
       asyncScrollY -= ((aMetrics.GetLayoutViewport().TopLeft() -
-                        aMetrics.GetVisualViewportOffset()) *
+                        aMetrics.GetVisualScrollOffset()) *
                        effectiveZoom)
                           .y;
     }
@@ -3839,7 +3839,7 @@ LayerToParentLayerMatrix4x4 APZCTreeManager::ComputeTransformForScrollThumb(
 
     if (gfxPlatform::UseDesktopZoomingScrollbars()) {
       asyncScrollX -= ((aMetrics.GetLayoutViewport().TopLeft() -
-                        aMetrics.GetVisualViewportOffset()) *
+                        aMetrics.GetVisualScrollOffset()) *
                        effectiveZoom)
                           .x;
     }

gfx/layers/apz/src/AsyncPanZoomController.cpp

@@ -4244,7 +4244,7 @@ CSSPoint AsyncPanZoomController::GetEffectiveScrollOffset(
     AsyncTransformConsumer aMode,
     const RecursiveMutexAutoLock& aProofOfLock) const {
   if (aMode == eForCompositing && mScrollMetadata.IsApzForceDisabled()) {
-    return mLastContentPaintMetrics.GetVisualViewportOffset();
+    return mLastContentPaintMetrics.GetVisualScrollOffset();
   }
   if (aMode == eForCompositing) {
     return mSampledState.front().GetScrollOffset();
@@ -4831,8 +4831,8 @@ void AsyncPanZoomController::NotifyLayersUpdated(
   if (visualScrollOffsetUpdated) {
     APZC_LOG("%p updating visual scroll offset from %s to %s\n", this,
              ToString(Metrics().GetVisualScrollOffset()).c_str(),
-             ToString(aLayerMetrics.GetVisualViewportOffset()).c_str());
-    Metrics().ClampAndSetScrollOffset(aLayerMetrics.GetVisualViewportOffset());
+             ToString(aLayerMetrics.GetVisualScrollOffset()).c_str());
+    Metrics().ClampAndSetScrollOffset(aLayerMetrics.GetVisualScrollOffset());
 
     // The rest of this branch largely follows the code in the
     // |if (scrollOffsetUpdated)| branch above.

gfx/layers/apz/test/gtest/TestBasic.cpp

@@ -475,7 +475,7 @@ TEST_F(APZCBasicTester, ResumeInterruptedTouchDrag_Bug1592435) {
   mainThreadOffset = scrollOffsetBeforeInterruption;
   mainThreadOffset.y -= 5;
   metadata = apzc->GetScrollMetadata();
-  metadata.GetMetrics().SetVisualViewportOffset(mainThreadOffset);
+  metadata.GetMetrics().SetVisualScrollOffset(mainThreadOffset);
   metadata.GetMetrics().SetScrollGeneration(2);
   metadata.GetMetrics().SetVisualScrollUpdateType(FrameMetrics::eMainThread);
   apzc->NotifyLayersUpdated(metadata, false, true);

gfx/layers/ipc/LayersMessageUtils.h

@@ -210,7 +210,6 @@ struct ParamTraits<mozilla::layers::FrameMetrics>
     WriteParam(aMsg, aParam.mExtraResolution);
     WriteParam(aMsg, aParam.mPaintRequestTime);
     WriteParam(aMsg, aParam.mScrollUpdateType);
-    WriteParam(aMsg, aParam.mVisualViewportOffset);
     WriteParam(aMsg, aParam.mVisualScrollUpdateType);
     WriteParam(aMsg, aParam.mFixedLayerMargins);
     WriteParam(aMsg, aParam.mPureRelativeOffset);
@@ -243,7 +242,6 @@ struct ParamTraits<mozilla::layers::FrameMetrics>
         ReadParam(aMsg, aIter, &aResult->mExtraResolution) &&
         ReadParam(aMsg, aIter, &aResult->mPaintRequestTime) &&
         ReadParam(aMsg, aIter, &aResult->mScrollUpdateType) &&
-        ReadParam(aMsg, aIter, &aResult->mVisualViewportOffset) &&
         ReadParam(aMsg, aIter, &aResult->mVisualScrollUpdateType) &&
         ReadParam(aMsg, aIter, &aResult->mFixedLayerMargins) &&
         ReadParam(aMsg, aIter, &aResult->mPureRelativeOffset) &&

layout/base/nsLayoutUtils.cpp

@@ -9282,8 +9282,6 @@ ScrollMetadata nsLayoutUtils::ComputeScrollMetadata(
             : layoutScrollOffset;
     metrics.SetVisualScrollOffset(visualScrollOffset);
     metrics.SetBaseScrollOffset(apzScrollPosition);
-    // FIXME: This is redundant now.
-    metrics.SetVisualViewportOffset(visualScrollOffset);
 
     if (aIsRootContent) {
       if (aLayerManager->GetIsFirstPaint() &&
@@ -9296,7 +9294,7 @@ ScrollMetadata nsLayoutUtils::ComputeScrollMetadata(
 
       if (const Maybe<PresShell::VisualScrollUpdate>& visualUpdate =
               presShell->GetPendingVisualScrollUpdate()) {
-        metrics.SetVisualViewportOffset(
+        metrics.SetVisualScrollOffset(
             CSSPoint::FromAppUnits(visualUpdate->mVisualScrollOffset));
         metrics.SetVisualScrollUpdateType(visualUpdate->mUpdateType);
         presShell->AcknowledgePendingVisualScrollUpdate();