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

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

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef InspectorDOMSnapshotAgent_h
+#define InspectorDOMSnapshotAgent_h
+
+#include "core/CSSPropertyNames.h"
+#include "core/inspector/InspectorBaseAgent.h"
+#include "core/inspector/protocol/DOMSnapshot.h"
+#include "platform/wtf/HashMap.h"
+#include "platform/wtf/Vector.h"
+
+namespace blink {
+
+class Element;
+class InspectedFrames;
+class Node;
+
+class CORE_EXPORT InspectorDOMSnapshotAgent final
+    : public InspectorBaseAgent<protocol::DOMSnapshot::Metainfo> {
+  WTF_MAKE_NONCOPYABLE(InspectorDOMSnapshotAgent);
+
+ public:
+  static InspectorDOMSnapshotAgent* Create(InspectedFrames* inspected_frames) {
+    return new InspectorDOMSnapshotAgent(inspected_frames);
+  }
+
+  ~InspectorDOMSnapshotAgent() override;
+  DECLARE_VIRTUAL_TRACE();
+
+  protocol::Response getSnapshot(
+      std::unique_ptr<protocol::Array<String>> style_whitelist,
+      std::unique_ptr<protocol::Array<protocol::DOMSnapshot::DOMNode>>*
+          dom_nodes,
+      std::unique_ptr<protocol::Array<protocol::DOMSnapshot::LayoutTreeNode>>*
+          layout_tree_nodes,
+      std::unique_ptr<protocol::Array<protocol::DOMSnapshot::ComputedStyle>>*
+          computed_styles) override;
+
+ private:
+  explicit InspectorDOMSnapshotAgent(InspectedFrames*);
+
+  // Adds a DOMNode for the given Node to |dom_nodes_| and returns its index.
+  int VisitNode(Node*);
+  std::unique_ptr<protocol::Array<int>> VisitContainerChildren(Node* container);
+  std::unique_ptr<protocol::Array<int>> VisitPseudoElements(Element* parent);
+  std::unique_ptr<protocol::Array<protocol::DOMSnapshot::NameValue>>
+  BuildArrayForElementAttributes(Element*);
+
+  // Adds a LayoutTreeNode for the LayoutObject of the given Node to
+  // |layout_tree_nodes_| and returns its index. Returns -1 if the Node has no
+  // associated LayoutObject.
+  int VisitLayoutTreeNode(Node*, int node_index);
+
+  // Returns the index of the ComputedStyle in |computed_styles_| for the given
+  // Node. Adds a new ComputedStyle if necessary, but ensures no duplicates are
+  // added to |computed_styles_|. Returns -1 if the node has no values for
+  // styles in |style_whitelist_|.
+  int GetStyleIndexForNode(Node*);
+
+  struct VectorStringHashTraits;
+  using ComputedStylesMap = WTF::HashMap<Vector<String>,
+                                         int,
+                                         VectorStringHashTraits,
+                                         VectorStringHashTraits>;
+  using CSSPropertyWhitelist = Vector<std::pair<String, CSSPropertyID>>;
+
+  // State of current snapshot.
+  std::unique_ptr<protocol::Array<protocol::DOMSnapshot::DOMNode>> dom_nodes_;
+  std::unique_ptr<protocol::Array<protocol::DOMSnapshot::LayoutTreeNode>>
+      layout_tree_nodes_;
+  std::unique_ptr<protocol::Array<protocol::DOMSnapshot::ComputedStyle>>
+      computed_styles_;
+  // Maps a style string vector to an index in |computed_styles_|. Used to avoid
+  // duplicate entries in |computed_styles_|.
+  std::unique_ptr<ComputedStylesMap> computed_styles_map_;
+  std::unique_ptr<Vector<std::pair<String, CSSPropertyID>>>
+      css_property_whitelist_;
+
+  Member<InspectedFrames> inspected_frames_;
+};
+
+}  // namespace blink
+
+#endif  // !defined(InspectorDOMSnapshotAgent_h)