Enable proper zooming of checkbox and radio button on Win and Mac.

Source/core/rendering/RenderThemeChromiumMac.h

Index: Source/core/rendering/RenderThemeChromiumMac.h
diff --git a/Source/core/rendering/RenderThemeChromiumMac.h b/Source/core/rendering/RenderThemeChromiumMac.h
index f161f5c9f30f47ab4cb2baf4f2514f339e5fa695..0c950fa4741989fdb5a2f0e143892fbc4154694d 100644
--- a/Source/core/rendering/RenderThemeChromiumMac.h
+++ b/Source/core/rendering/RenderThemeChromiumMac.h
@@ -202,6 +202,8 @@ protected:
     // A view associated to the contained document. Subclasses may not have such a view and return a fake.
     NSView* documentViewFor(RenderObject*) const;
 
+    virtual bool shouldUseFallbackTheme(RenderStyle*) const OVERRIDE;
+
 private:
     virtual Color disabledTextColor(const Color& textColor, const Color&) const OVERRIDE { return textColor; }
     virtual void updateActiveState(NSCell*, const RenderObject*);