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

Source/core/rendering/RenderThemeChromiumWin.cpp

Index: Source/core/rendering/RenderThemeChromiumWin.cpp
diff --git a/Source/core/rendering/RenderThemeChromiumWin.cpp b/Source/core/rendering/RenderThemeChromiumWin.cpp
index c1c901fd6fd4d099f3a38ecd00f919aea8dca2f7..3e9ddc7cf47271654e24424be2f501085db76409 100644
--- a/Source/core/rendering/RenderThemeChromiumWin.cpp
+++ b/Source/core/rendering/RenderThemeChromiumWin.cpp
@@ -654,4 +654,12 @@ bool RenderThemeChromiumWin::shouldOpenPickerWithF4Key() const
     return true;
 }
 
+bool RenderThemeChromiumWin::shouldUseFallbackTheme(RenderStyle* style) const
+{
+    ControlPart part = style->appearance();
+    if (part == CheckboxPart || part == RadioPart)
+        return style->effectiveZoom() != 1;
+    return false;
+}
+
 } // namespace WebCore