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..42272dc4f302ee88057fe67eb549dd30b365d281 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, false, delta.width(), delta.height());
 
     FloatSize remainingDelta = delta;
 
@@ -737,14 +736,16 @@ bool LocalFrame::applyScrollDelta(const FloatSize& delta, bool isScrollBegin)
         remainingDelta = host()->topControls().scrollBy(remainingDelta);
 
     if (remainingDelta.isZero())
-        return true;
+        return ScrollResult(delta.width(), delta.height(), 0.0f, 0.0f);

[MuVen, 2015/06/02 09:04:00]

Even this returns didScrollX, didScrollY. ple let me know your input.

[majidvp, 2015/06/02 17:00:31]

This looks reasonable.

[MuVen, 2015/06/03 09:32:18]

Done.

 
-    bool consumed = remainingDelta != delta;
+    ScrollResult result = scrollAreaOnBothAxes(remainingDelta, *view()->scrollableArea());
 
-    if (scrollAreaOnBothAxes(remainingDelta, *view()->scrollableArea()))
-        return true;
+    if (result.didScroll())
+        return result;

[majidvp, 2015/06/02 17:00:31]

I believe this is no longer correct. Consider this situation where the top
control consumes vertical scroll and the view consumes horizontal scroll. The
final result should have didScroll true for both orientation which is not the
case with this logic.

You can get rid of this conditional and instead use the two computations below.

[MuVen, 2015/06/03 09:32:18]

Done.

 
-    return consumed;
+    result.didScrollX = remainingDelta.width() != delta.width();
+    result.didScrollY = remainingDelta.height() != delta.height();

[majidvp, 2015/06/02 17:00:31]

If you get rid of the conditional above and replace these with

result.didScrollX = result.didScrollX || (remainingDelta.width() !=
delta.width())
...

[MuVen, 2015/06/03 09:32:18]

Done.

+    return result;
 }
 
 bool LocalFrame::shouldScrollTopControls(const FloatSize& delta) const