DevTools: handle zoom shortcuts in hosted mode on Mac OS X

The Ctrl+/Ctrl- shortcuts are already supported in hosted mode on linux
for some time. This patch adds the same supoprt for Cmd+/Cmd- shortcuts
on mac in hosted mode.

TBR=pfeldman

Review URL: https://codereview.chromium.org/702583003

git-svn-id: svn://svn.chromium.org/blink/trunk@184867 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/devtools/front_end/host/InspectorFrontendHost.js

@@ -306,7 +306,8 @@ WebInspector.InspectorFrontendHostStub = function()
     function stopEventPropagation(event)
     {
         // Let browser handle Ctrl+/Ctrl- shortcuts in hosted mode.
-        if (event.ctrlKey && (event.keyCode === 187 || event.keyCode === 189))
+        var zoomModifier = WebInspector.isMac() ? event.metaKey : event.ctrlKey;
+        if (zoomModifier && (event.keyCode === 187 || event.keyCode === 189))
             event.stopPropagation();
     }
     document.addEventListener("keydown", stopEventPropagation, true);