Let page zoom affect resolution and -webkit-device-pixel-ratio MQs.

Source/core/page/Frame.h

Index: Source/core/page/Frame.h
diff --git a/Source/core/page/Frame.h b/Source/core/page/Frame.h
index 47fdc5a1275891106f5e42c660a8e8b542016a08..b954a8d04052f9468d3cbdedb02e8041ce4113cb 100644
--- a/Source/core/page/Frame.h
+++ b/Source/core/page/Frame.h
@@ -136,6 +136,9 @@ namespace WebCore {
 
         void deviceOrPageScaleFactorChanged();
 
+        // Returns the resolution in device pixels per CSS pixel.
+        float resolutionDPPX() const;
+
 #if ENABLE(ORIENTATION_EVENTS)
         // Orientation is the interface orientation in degrees. Some examples are:
         //  0 is straight up; -90 is when the device is rotated 90 clockwise;