Compute the popup location/size correctly when use-zoom-for-dsf is enabled.

content/renderer/render_widget.h

Index: content/renderer/render_widget.h
diff --git a/content/renderer/render_widget.h b/content/renderer/render_widget.h
index d062a1f2cbd45b981704a6edd0a2a80fdd8b16f3..f521c9a271d1a274e39b54ee74a494bccd17b8d5 100644
--- a/content/renderer/render_widget.h
+++ b/content/renderer/render_widget.h
@@ -196,6 +196,7 @@ class CONTENT_EXPORT RenderWidget
                      const blink::WebFloatPoint& position,
                      const blink::WebFloatSize& velocity) override;
   void showImeIfNeeded() override;
+  void convertViewportToScreen(blink::WebRect* rect) override;
 
 #if defined(OS_ANDROID)
   // Notifies that a tap was not consumed, so showing a UI for the unhandled
@@ -439,6 +440,10 @@ class CONTENT_EXPORT RenderWidget
   virtual void OnImeConfirmComposition(const base::string16& text,
                                        const gfx::Range& replacement_range,
                                        bool keep_selection);
+  // Called when the device scale factor is changed, or the layer tree is
+  // initialized.
+  virtual void OnDeviceScaleFactorChanged();
+
   void OnRepaint(gfx::Size size_to_paint);
   void OnSyntheticGestureCompleted();
   void OnSetTextDirection(blink::WebTextDirection direction);