Reviewed by Pavel Feldman.

        Web Inspector: There is a validator of the protocol message format.

        It has two parts. InspectorBackendStub.js is the frontend part.
        InspectorBackendDispatcher.cpp is the backend part.
        Both parts are checking protocol message format and report the error if
        the message has not enough fields or the types of fields do not match with
        Inspector.idl specification. These validators are generated automatically.

        In addition, we have a number of places at the backend where we check the
        function arguments and do nothing if the arguments are invalid
        from the business logic point of view.

        This patch bring us an ability to report a custom error from such function to the frontend.

        https://bugs.webkit.org/show_bug.cgi?id=54971

        * inspector/CodeGeneratorInspector.pm:
        * inspector/InjectedScriptHost.cpp:
        * inspector/InspectorAgent.cpp:
        * inspector/InspectorAgent.h:
        * inspector/InspectorApplicationCacheAgent.cpp:
        * inspector/InspectorApplicationCacheAgent.h:
        * inspector/InspectorBrowserDebuggerAgent.cpp:
        * inspector/InspectorBrowserDebuggerAgent.h:
        * inspector/InspectorCSSAgent.cpp:
        * inspector/InspectorCSSAgent.h:
        * inspector/InspectorConsoleAgent.cpp:
        * inspector/InspectorConsoleAgent.h:
        * inspector/InspectorController.cpp:
        * inspector/InspectorDOMAgent.cpp:
        * inspector/InspectorDOMAgent.h:
        * inspector/InspectorDOMStorageAgent.cpp:
        * inspector/InspectorDOMStorageAgent.h:
        * inspector/InspectorDatabaseAgent.cpp:
        * inspector/InspectorDatabaseAgent.h:
        * inspector/InspectorDebuggerAgent.cpp:
        * inspector/InspectorDebuggerAgent.h:
        * inspector/InspectorProfilerAgent.cpp:
        * inspector/InspectorProfilerAgent.h:
        * inspector/InspectorResourceAgent.cpp:
        * inspector/InspectorResourceAgent.h:
        * inspector/InspectorRuntimeAgent.cpp:
        * inspector/InspectorRuntimeAgent.h:
        * inspector/InspectorTimelineAgent.cpp:
        * inspector/InspectorTimelineAgent.h:




git-svn-id: http://svn.webkit.org/repository/webkit/trunk@79539 268f45cc-cd09-0410-ab3c-d52691b4dbfc