OverscrollGlow for mainThread-{BLINK CHANGES}

Source/core/frame/LocalFrame.cpp

Index: Source/core/frame/LocalFrame.cpp
diff --git a/Source/core/frame/LocalFrame.cpp b/Source/core/frame/LocalFrame.cpp
index f5a0e0366599c39e4b4a3ddcb51b16f1987cdc8a..a654381bc9f47ac646da5a0888829a297b09626a 100644
--- a/Source/core/frame/LocalFrame.cpp
+++ b/Source/core/frame/LocalFrame.cpp
@@ -714,21 +714,20 @@ void LocalFrame::removeSpellingMarkersUnderWords(const Vector<String>& words)
     spellChecker().removeSpellingMarkersUnderWords(words);
 }
 
-static bool scrollAreaOnBothAxes(const FloatSize& delta, ScrollableArea& view)
+static ScrollResult scrollAreaOnBothAxes(const FloatSize& delta, ScrollableArea& view)
 {
-    bool scrolledHorizontal = view.scroll(ScrollLeft, ScrollByPrecisePixel, delta.width());
-    bool scrolledVertical = view.scroll(ScrollUp, ScrollByPrecisePixel, delta.height());
-    return scrolledHorizontal || scrolledVertical;
+    ScrollResultOneDimensional horizontal = view.scroll(ScrollLeft, ScrollByPrecisePixel, delta.width());
+    ScrollResultOneDimensional vertical = view.scroll(ScrollUp, ScrollByPrecisePixel, delta.height());
+    return ScrollResult((horizontal.didScroll || vertical.didScroll), horizontal.unusedScrollDelta, vertical.unusedScrollDelta);
 }
 
-// Returns true if a scroll occurred.
-bool LocalFrame::applyScrollDelta(const FloatSize& delta, bool isScrollBegin)
+ScrollResult LocalFrame::applyScrollDelta(const FloatSize& delta, bool isScrollBegin)
 {
     if (isScrollBegin)
         host()->topControls().scrollBegin();
 
     if (!view() || delta.isZero())
-        return false;
+        return ScrollResult(false, delta.width(), delta.height());
 
     FloatSize remainingDelta = delta;
 
@@ -737,14 +736,15 @@ bool LocalFrame::applyScrollDelta(const FloatSize& delta, bool isScrollBegin)
         remainingDelta = host()->topControls().scrollBy(remainingDelta);
 
     if (remainingDelta.isZero())
-        return true;
+        return ScrollResult(true);
 
-    bool consumed = remainingDelta != delta;
+    ScrollResult result = scrollAreaOnBothAxes(remainingDelta, *view()->scrollableArea());
 
-    if (scrollAreaOnBothAxes(remainingDelta, *view()->scrollableArea()))
-        return true;
+    if (result.didScroll)
+        return result;
 
-    return consumed;
+    result.didScroll = remainingDelta != delta;
+    return result;
 }
 
 bool LocalFrame::shouldScrollTopControls(const FloatSize& delta) const