Ensure FrameView scrollbars are updated when changing device emulation modes

third_party/WebKit/Source/core/frame/VisualViewport.cpp

Index: third_party/WebKit/Source/core/frame/VisualViewport.cpp
diff --git a/third_party/WebKit/Source/core/frame/VisualViewport.cpp b/third_party/WebKit/Source/core/frame/VisualViewport.cpp
index 5585ea1d3d4f0a34b20b0eacda600d6e4948f973..a107295d05f2a2590d11c08cd009f60af2f26bda 100644
--- a/third_party/WebKit/Source/core/frame/VisualViewport.cpp
+++ b/third_party/WebKit/Source/core/frame/VisualViewport.cpp
@@ -424,6 +424,13 @@ void VisualViewport::initializeScrollbars() {
 
   setupScrollbar(WebScrollbar::Horizontal);
   setupScrollbar(WebScrollbar::Vertical);
+
+  // Ensure existing FrameView scrollbars are removed if the visual viewport
+  // scrollbars are now supplied, or created if the visual viewport no longer
+  // supplies scrollbars.
+  LocalFrame* frame = mainFrame();
+  if (frame && frame->view())
+    frame->view()->visualViewportScrollbarsChanged();
 }
 
 void VisualViewport::setupScrollbar(WebScrollbar::Orientation orientation) {