Convert main-thread overscroll parameters into viewport space.

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 93bff83380b1f00caf85f7d9be3e10e1bc9ce339..9f897771f495ff5c8aab603d52546a42915d1bba 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -2018,8 +2018,8 @@ void RenderWidget::didHandleGestureEvent(
 }
 
 void RenderWidget::didOverscroll(
-    const blink::WebFloatSize& unusedDelta,
-    const blink::WebFloatSize& accumulatedRootOverScroll,
+    const blink::WebFloatSize& overscrollDelta,
+    const blink::WebFloatSize& accumulatedOverscroll,
     const blink::WebFloatPoint& position,
     const blink::WebFloatSize& velocity) {
 #if defined(OS_MACOSX)
@@ -2029,7 +2029,7 @@ void RenderWidget::didOverscroll(
   if (!compositor_deps()->IsElasticOverscrollEnabled())
     return;
 #endif
-  input_handler_->DidOverscrollFromBlink(unusedDelta, accumulatedRootOverScroll,
+  input_handler_->DidOverscrollFromBlink(overscrollDelta, accumulatedOverscroll,
                                          position, velocity);
 }