Use fallback in LayoutThemeMobile on mac.

third_party/WebKit/LayoutTests/inspector-protocol/emulation/device-emulation-test.js

 function setMetaViewport(override)
 {
     var VIEWPORTS = {
         "w=320": "width=320",
         "w=dw": "width=device-width",
         "w=980": "width=980",
         "none": "no viewport (desktop site)"
     };
 
     var viewport = VIEWPORTS["none"];
@@ skipping 87 matching lines @@
         testMQDimension("height", document.documentElement.clientHeight);
     }
     testJS("document.documentElement.clientHeight");
     testJS("document.documentElement.offsetHeight");
     testJS("document.documentElement.scrollHeight");
     if (full)
         testJS("document.body.clientHeight");
     testJS("document.body.offsetHeight");
     testJS("document.body.scrollHeight");
 
+    var measured = document.querySelectorAll(".device-emulation-measure");
+    for (var i = 0; i < measured.length; ++i)
+        writeResult("measured " + measured[i].getAttribute("type") + ": " + measured[i].offsetWidth + "x" + measured[i].offsetHeight);
+
     return results.join("\n");
 }
 
 function testJS(expr, unit)
 {
     if (unit === undefined)
         unit = "px";
 
     var ans = eval(expr);
     if (typeof ans == "number")
@@ skipping 128 matching lines @@
     InspectorTest.emulateAndGetMetrics(width, height, deviceScaleFactor, viewport, insets, noReload, callback);
 
     function callback()
     {
         InspectorTest.log(InspectorTest._deviceEmulationResults.join("\n"));
         InspectorTest.completeTest();
     }
 };
 
 };