Update from https://crrev.com/315085

cc/layers/layer.cc

Index: cc/layers/layer.cc
diff --git a/cc/layers/layer.cc b/cc/layers/layer.cc
index face433a808db2c90727fb0b55880b4d3bddcf8e..01e67c5edc6d586ba12b677cfa11e33f8e9fb429 100644
--- a/cc/layers/layer.cc
+++ b/cc/layers/layer.cc
@@ -71,6 +71,7 @@ Layer::Layer()
       force_render_surface_(false),
       transform_is_invertible_(true),
       has_render_surface_(false),
+      scroll_blocks_on_(ScrollBlocksOnNone),
       background_color_(0),
       opacity_(1.f),
       blend_mode_(SkXfermode::kSrcOver_Mode),
@@ -758,6 +759,14 @@ void Layer::SetTouchEventHandlerRegion(const Region& region) {
   SetNeedsCommit();
 }
 
+void Layer::SetScrollBlocksOn(ScrollBlocksOn scroll_blocks_on) {
+  DCHECK(IsPropertyChangeAllowed());
+  if (scroll_blocks_on_ == scroll_blocks_on)
+    return;
+  scroll_blocks_on_ = scroll_blocks_on;
+  SetNeedsCommit();
+}
+
 void Layer::SetDrawCheckerboardForMissingTiles(bool checkerboard) {
   DCHECK(IsPropertyChangeAllowed());
   if (draw_checkerboard_for_missing_tiles_ == checkerboard)
@@ -911,6 +920,7 @@ void Layer::PushPropertiesTo(LayerImpl* layer) {
   layer->SetHaveScrollEventHandlers(have_scroll_event_handlers_);
   layer->SetNonFastScrollableRegion(non_fast_scrollable_region_);
   layer->SetTouchEventHandlerRegion(touch_event_handler_region_);
+  layer->SetScrollBlocksOn(scroll_blocks_on_);
   layer->SetContentsOpaque(contents_opaque_);
   if (!layer->OpacityIsAnimatingOnImplOnly() && !OpacityIsAnimating())
     layer->SetOpacity(opacity_);
@@ -978,10 +988,14 @@ void Layer::PushPropertiesTo(LayerImpl* layer) {
     layer->SetClipChildren(nullptr);
   }
 
-  layer->PushScrollOffsetFromMainThread(scroll_offset_);
-  if (layer_animation_controller_->scroll_offset_animation_was_interrupted() &&
-      layer->IsActive())
-    layer->SetScrollDelta(gfx::Vector2dF());
+  // When a scroll offset animation is interrupted the new scroll position on
+  // the pending tree will clobber any impl-side scrolling occuring on the
+  // active tree. To do so, avoid scrolling the pending tree along with it
+  // instead of trying to undo that scrolling later.
+  if (layer_animation_controller_->scroll_offset_animation_was_interrupted())
+    layer->PushScrollOffsetFromMainThreadAndClobberActiveValue(scroll_offset_);
+  else
+    layer->PushScrollOffsetFromMainThread(scroll_offset_);
   layer->SetScrollCompensationAdjustment(ScrollCompensationAdjustment());
 
   // Wrap the copy_requests_ in a PostTask to the main thread.