DevTools: remove dependency of most agents on InspectorPageAgent

Source/core/inspector/InspectorPageAgent.h

Index: Source/core/inspector/InspectorPageAgent.h
diff --git a/Source/core/inspector/InspectorPageAgent.h b/Source/core/inspector/InspectorPageAgent.h
index 5d009a8368c6e2e27b52bb82a6cdf44422d7a81d..e0ed700f88e379d31f46a7ced844dd0dff2c2e5f 100644
--- a/Source/core/inspector/InspectorPageAgent.h
+++ b/Source/core/inspector/InspectorPageAgent.h
@@ -124,11 +124,6 @@ public:
     void discardAgent() override;
 
     // Cross-agents API

[dgozman, 2015/04/24 13:16:14]

I thought all cross-agents methods are gone now.

[caseq, 2015/04/24 13:50:55]

resourceContentLoader() is still used by CSS agent (it should be possible to get
rid of it, too, but let's do it in a separate patch; screencastEnabled() is also
used by WebDevToolsAgentImpl).

findFrameWithSecurityOrigin() proved to be unused, so nuking it now.

-    static DocumentLoader* assertDocumentLoader(ErrorString*, LocalFrame*);
-    LocalFrame* frameForId(const String& frameId);
-    LocalFrame* assertFrame(ErrorString*, const String& frameId);
-    FrameHost* frameHost();
-    LocalFrame* inspectedFrame() const { return m_inspectedFrame.get(); }
     LocalFrame* findFrameWithSecurityOrigin(const String& originRawString);
     bool screencastEnabled();
     InspectorResourceContentLoader* resourceContentLoader() { return m_inspectorResourceContentLoader.get(); }
@@ -142,6 +137,7 @@ private:
 
     void finishReload();
     void getResourceContentAfterResourcesContentLoaded(const String& frameId, const String& url, PassRefPtrWillBeRawPtr<GetResourceContentCallback>);
+    LocalFrame* assertFrame(ErrorString*, const String& frameId);
 
     static bool dataContent(const char* data, unsigned size, const String& textEncodingName, bool withBase64Encode, String* result);