Devtools [LayoutEditor]: show selector info and highlight affected nodes

Source/core/inspector/LayoutEditor.h

 // Copyright 2015 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 LayoutEditor_h
 #define LayoutEditor_h
 
 #include "core/CSSPropertyNames.h"
 #include "core/CoreExport.h"
 #include "core/css/CSSPrimitiveValue.h"
+#include "core/css/CSSStyleRule.h"
 #include "core/dom/Element.h"
 #include "platform/heap/Handle.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/RefPtr.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class CSSPrimitiveValue;
 class InspectorCSSAgent;
 class InspectorDOMAgent;
 class JSONArray;
 class JSONObject;
 
 class CORE_EXPORT LayoutEditor final : public NoBaseWillBeGarbageCollectedFinalized<LayoutEditor> {
 public:
     static PassOwnPtrWillBeRawPtr<LayoutEditor> create(InspectorCSSAgent* cssAgent, InspectorDOMAgent* domAgent)
     {
         return adoptPtrWillBeNoop(new LayoutEditor(cssAgent, domAgent));
     }
 
     void selectNode(Node*);
     Node* node() { return m_element.get(); }
     PassRefPtr<JSONObject> buildJSONInfo() const;
     void overlayStartedPropertyChange(const String&);
     void overlayPropertyChanged(float);
     void overlayEndedPropertyChange();
     void clearSelection(bool);
+    void nextSelector();
+    void previousSelector();
+    String currentSelectorInfo();
 
     DECLARE_TRACE();
 
 private:
     LayoutEditor(InspectorCSSAgent*, InspectorDOMAgent*);
     RefPtrWillBeRawPtr<CSSPrimitiveValue> getPropertyCSSValue(CSSPropertyID) const;
     PassRefPtr<JSONObject> createValueDescription(const String&) const;
     void appendAnchorFor(JSONArray*, const String&, const String&, const FloatPoint&, const FloatPoint&) const;
+    void initializeCSSRules();
 
     RefPtrWillBeMember<Element> m_element;
     RawPtrWillBeMember<InspectorCSSAgent> m_cssAgent;
     RawPtrWillBeMember<InspectorDOMAgent> m_domAgent;
     CSSPropertyID m_changingProperty;
     float m_propertyInitialValue;
     float m_factor;
     CSSPrimitiveValue::UnitType m_valueUnitType;
     bool m_isDirty;
+
+    WillBeHeapVector<RefPtrWillBeMember<CSSStyleRule>> m_matchedRules;
+    HashMap<int, String> m_cachedSelectorsInfo;
+    // -1 means "inline style".
+    int m_currentRuleIndex;
 };
 
 } // namespace blink
 
 
 #endif // !defined(LayoutEditor_h)