Reviewed by Pavel Feldman.

        Web Inspector: move agents from InspectorAgent to InspectorController
        https://bugs.webkit.org/show_bug.cgi?id=60359

        All inspector agents are now created and owned by InspectorController which
        in turned is owned by the inspected Page. InspectorInstrumentation gets access
        to the instrumenting agents by means of InspectorAgent::instrumentingAgents().

        In addition to managing inspector agents lifetime InspectorController sets
        InspectorFronted on the agents when the front-end is connected.

        * inspector/InspectorAgent.cpp:
        (WebCore::InspectorAgent::InspectorAgent):
        (WebCore::InspectorAgent::~InspectorAgent):
        (WebCore::InspectorAgent::inspectedPageDestroyed):
        (WebCore::InspectorAgent::restore):
        (WebCore::InspectorAgent::setFrontend):
        (WebCore::InspectorAgent::clearFrontend):
        * inspector/InspectorAgent.h: all accessors to other agents were removed along with
        the agents themselves from InspectorAgent. Every agent that depends on some other agents
        receives pointers to them explicitely in its constructor. All access to the agents
        from WebCore should go through InspectorInstrumentation which retrieves corresponding
        agents using InstrumentingAgents structure which represents the set of active agents.
        (WebCore::InspectorAgent::instrumentingAgents):
        * inspector/InspectorController.cpp:
        (WebCore::InspectorController::InspectorController):
        (WebCore::InspectorController::~InspectorController):
        (WebCore::InspectorController::inspectedPageDestroyed):
        (WebCore::InspectorController::startTimelineProfiler):
        (WebCore::InspectorController::stopTimelineProfiler):
        (WebCore::InspectorController::connectFrontend):
        (WebCore::InspectorController::disconnectFrontend):
        (WebCore::InspectorController::restoreInspectorStateFromCookie):
        (WebCore::InspectorController::drawNodeHighlight):
        (WebCore::InspectorController::inspect):
        (WebCore::InspectorController::timelineProfilerEnabled):
        (WebCore::InspectorController::hideHighlight):
        (WebCore::InspectorController::highlightedNode):
        (WebCore::InspectorController::enableProfiler):
        (WebCore::InspectorController::disableProfiler):
        (WebCore::InspectorController::profilerEnabled):
        (WebCore::InspectorController::debuggerEnabled):
        (WebCore::InspectorController::disableDebugger):
        (WebCore::InspectorController::startUserInitiatedProfiling):
        (WebCore::InspectorController::stopUserInitiatedProfiling):
        (WebCore::InspectorController::isRecordingUserInitiatedProfile):
        (WebCore::InspectorController::resume):
        * inspector/InspectorController.h:
        * inspector/InspectorInstrumentation.cpp:
        (WebCore::InspectorInstrumentation::didInsertDOMNodeImpl):
        (WebCore::InspectorInstrumentation::didRemoveDOMNodeImpl):
        (WebCore::InspectorInstrumentation::didModifyDOMAttrImpl):
        (WebCore::InspectorInstrumentation::didInvalidateStyleAttrImpl):
        (WebCore::InspectorInstrumentation::characterDataModifiedImpl):
        (WebCore::InspectorInstrumentation::didReceiveResourceResponseImpl):
        (WebCore::InspectorInstrumentation::didFailLoadingImpl):
        (WebCore::InspectorInstrumentation::resourceRetrievedByXMLHttpRequestImpl):
        (WebCore::InspectorInstrumentation::addMessageToConsoleImpl):
        (WebCore::InspectorInstrumentation::consoleCountImpl):
        (WebCore::InspectorInstrumentation::startConsoleTimingImpl):
        (WebCore::InspectorInstrumentation::stopConsoleTimingImpl):
        (WebCore::InspectorInstrumentation::addStartProfilingMessageToConsoleImpl):
        (WebCore::InspectorInstrumentation::addProfileImpl):
        (WebCore::InspectorInstrumentation::getCurrentUserInitiatedProfileNameImpl):
        (WebCore::InspectorInstrumentation::profilerEnabledImpl):
        (WebCore::InspectorInstrumentation::cancelPauseOnNativeEvent):
        * page/Page.cpp:
        (WebCore::Page::~Page): we send two notifications when inspected Page is being
        destroyed: one to the inspector instrumentation and another one to the InspectorController
        which is owned by the Page.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@86327 268f45cc-cd09-0410-ab3c-d52691b4dbfc