Update inspector classes to use OVERRIDE / FINAL when needed

Source/core/inspector/InspectorMemoryAgent.h

Index: Source/core/inspector/InspectorMemoryAgent.h
diff --git a/Source/core/inspector/InspectorMemoryAgent.h b/Source/core/inspector/InspectorMemoryAgent.h
index 6b202a86d2494cc6736f8cbda48a3d9c4892a765..b8d773dec5f187f9909e2b4856dbcac429c0f075 100644
--- a/Source/core/inspector/InspectorMemoryAgent.h
+++ b/Source/core/inspector/InspectorMemoryAgent.h
@@ -41,7 +41,7 @@ class InstrumentingAgents;
 
 typedef String ErrorString;
 
-class InspectorMemoryAgent : public InspectorBaseAgent<InspectorMemoryAgent>, public InspectorBackendDispatcher::MemoryCommandHandler {
+class InspectorMemoryAgent FINAL : public InspectorBaseAgent<InspectorMemoryAgent>, public InspectorBackendDispatcher::MemoryCommandHandler {
     WTF_MAKE_NONCOPYABLE(InspectorMemoryAgent);
 public:
     static PassOwnPtr<InspectorMemoryAgent> create(InstrumentingAgents* instrumentingAgents, InspectorCompositeState* state)
@@ -50,10 +50,10 @@ public:
     }
     virtual ~InspectorMemoryAgent();
 
-    virtual void getDOMCounters(ErrorString*, int* documents, int* nodes, int* jsEventListeners);
+    virtual void getDOMCounters(ErrorString*, int* documents, int* nodes, int* jsEventListeners) OVERRIDE;
 
-    virtual void setFrontend(InspectorFrontend*);
-    virtual void clearFrontend();
+    virtual void setFrontend(InspectorFrontend*) OVERRIDE;
+    virtual void clearFrontend() OVERRIDE;
 
 private:
     InspectorMemoryAgent(InstrumentingAgents*, InspectorCompositeState*);