[Android] Suppress overscroll for unscrollable axes in the browser

cc/layers/viewport.cc

Index: cc/layers/viewport.cc
diff --git a/cc/layers/viewport.cc b/cc/layers/viewport.cc
index 059e0a491a9f5bbc20a12448edf69d274d7b566c..639ed8c9e32b4e83e6659a01ae1e02a4642f9240 100644
--- a/cc/layers/viewport.cc
+++ b/cc/layers/viewport.cc
@@ -160,16 +160,6 @@ gfx::Vector2dF Viewport::AdjustOverscroll(const gfx::Vector2dF& delta) const {
   if (std::abs(adjusted.y()) < kEpsilon)
     adjusted.set_y(0.0f);

[tdresser, 2015/07/10 18:41:30]

Why can't these be moved?

[jdduke (slow), 2015/07/10 19:12:50]

So, the problem is that we're often seeing small residual overscroll deltas
after nearly ever scroll (~.01 or less) even when the "full" scroll delta has
been consume. Ideally we'd fix that, but it seems to also happen on the Blink
thread so maybe there's something more fundamental. In any case, we don't want
to report overscroll when we've logically consumed the entire scroll delta.

 
-  // Disable overscroll on axes which are impossible to scroll.
-  if (host_impl_->settings().report_overscroll_only_for_scrollable_axes) {
-    if (std::abs(MaxTotalScrollOffset().x()) <= kEpsilon ||
-        !InnerScrollLayer()->user_scrollable_horizontal())
-      adjusted.set_x(0.0f);
-    if (std::abs(MaxTotalScrollOffset().y()) <= kEpsilon ||
-        !InnerScrollLayer()->user_scrollable_vertical())
-      adjusted.set_y(0.0f);
-  }
-
   return adjusted;
 }