When moving past a left-hand scrollbar, don't jump way outside the content box.

third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 603 matching lines @@
   FloatingObject* new_floating_object = floating_objects_->Add(
       floating_object->CopyToNewContainer(offset, false, true));
   new_floating_object->SetIsLowestNonOverhangingFloatInChild(true);
 }
 
 DISABLE_CFI_PERF
 void LayoutBlockFlow::DetermineLogicalLeftPositionForChild(LayoutBox& child) {
   LayoutUnit start_position = BorderStart() + PaddingStart();
   LayoutUnit initial_start_position = start_position;
   if (ShouldPlaceBlockDirectionScrollbarOnLogicalLeft())
-    start_position -= VerticalScrollbarWidth();
+    start_position -= VerticalScrollbarWidthClampedToContentBox();
   LayoutUnit total_available_logical_width =
       BorderAndPaddingLogicalWidth() + AvailableLogicalWidth();
 
   LayoutUnit child_margin_start = MarginStartForChild(child);
   LayoutUnit new_position = start_position + child_margin_start;
 
   if (child.AvoidsFloats() && ContainsFloats()) {
     LayoutUnit position_to_avoid_floats =
         StartOffsetForLine(LogicalTopForChild(child), kDoNotIndentText,
                            LogicalHeightForChild(child));
@@ skipping 4059 matching lines @@
   return LayoutBlock::DeprecatedInvalidatePaint(paint_invalidation_state);
 }
 
 void LayoutBlockFlow::InvalidateDisplayItemClients(
     PaintInvalidationReason invalidation_reason) const {
   BlockFlowPaintInvalidator(*this).InvalidateDisplayItemClients(
       invalidation_reason);
 }
 
 }  // namespace blink