Web Inspector: Fix keyboard shortcuts for other platforms
        https://bugs.webkit.org/show_bug.cgi?id=120657

        Reviewed by NOBODY (OOPS!).

        Handling keyboard shortcuts according to the current platform.

        * UserInterface/InspectorFrontendHostStub.js:
        (.WebInspector.InspectorFrontendHostStub.prototype.loadResourceSynchronously):
        (.WebInspector.InspectorFrontendHostStub.prototype.platform): Added. Return the
        current platform.
        * UserInterface/KeyboardShortcut.js:
        (WebInspector.KeyboardShortcut.Modifier.get CommandOrControl): Added. Created keyboard
        modifier to return Control or Command key according to current platform.
        * UserInterface/ContentBrowser.js:
        (WebInspector.ContentBrowser): Returning Control or Command key for keyboard
        shortcuts according to current platform.
        * UserInterface/DebuggerSidebarPanel.js:
        (WebInspector.DebuggerSidebarPanel): Ditto.
        * UserInterface/FindBanner.js:
        (WebInspector.FindBanner): Ditto.
        * UserInterface/JavaScriptLogViewController.js:
        (WebInspector.JavaScriptLogViewController): Ditto.
        * UserInterface/LogContentView.js:
        (WebInspector.LogContentView): Ditto.
        * UserInterface/Main.js:
        (WebInspector.contentLoaded): Ditto.
        * UserInterface/ResourceSidebarPanel.js:
        (WebInspector.ResourceSidebarPanel): Ditto.