[devtools] Add DOMSnapshot domain for dom+layout+style snapshots.

third_party/WebKit/Source/core/inspector/InspectorDOMAgent.h

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 203 matching lines @@
 
   Node* NodeForId(int node_id);
   int BoundNodeId(Node*);
   void SetDOMListener(DOMListener*);
   int PushNodePathToFrontend(Node*);
   protocol::Response PushDocumentUponHandlelessOperation();
   protocol::Response NodeForRemoteObjectId(const String& remote_object_id,
                                            Node*&);
 
   static String DocumentURLString(Document*);
+  static String DocumentBaseURLString(Document*);
 
   std::unique_ptr<v8_inspector::protocol::Runtime::API::RemoteObject>
   ResolveNode(Node*, const String& object_group);
 
   InspectorHistory* History() { return history_.Get(); }
 
   // We represent embedded doms as a part of the same hierarchy. Hence we treat
   // children of frame owners differently.  We also skip whitespace text nodes
   // conditionally. Following methods encapsulate these specifics.
   static Node* InnerFirstChild(Node*);
@@ skipping 81 matching lines @@
   SearchResults search_results_;
   Member<InspectorRevalidateDOMTask> revalidate_task_;
   Member<InspectorHistory> history_;
   Member<DOMEditor> dom_editor_;
   bool suppress_attribute_modified_event_;
 };
 
 }  // namespace blink
 
 #endif  // !defined(InspectorDOMAgent_h)