DevTools: explicitly control support for viewport meta tag so that desktop emulation was possible

LayoutTests/inspector/styles/override-screen-size.html

Index: LayoutTests/inspector/styles/override-screen-size.html
diff --git a/LayoutTests/inspector/styles/override-screen-size.html b/LayoutTests/inspector/styles/override-screen-size.html
index 0843385974dc3a43910ef839d56e12cbae2501d5..0a949a902f124415e882f8201569780ea62a6d30 100644
--- a/LayoutTests/inspector/styles/override-screen-size.html
+++ b/LayoutTests/inspector/styles/override-screen-size.html
@@ -123,7 +123,7 @@ function test()
         }
         
         var enabled = width != 0 || height != 0;
-        PageAgent.setDeviceMetricsOverride(width, height, 1, true, callback);
+        PageAgent.setDeviceMetricsOverride(width, height, 1, false, true, callback);
         overridesEnabled = enabled;
     }