Reapply 169371 "DevTools: defer styles delta calculation to until the end of the task"

Source/core/inspector/InspectorCSSAgent.h

Index: Source/core/inspector/InspectorCSSAgent.h
diff --git a/Source/core/inspector/InspectorCSSAgent.h b/Source/core/inspector/InspectorCSSAgent.h
index d10435884235da226803b8fc0c132d3f79c636e4..bd5ed15198b512552bc83156b04e3f703a5e202c 100644
--- a/Source/core/inspector/InspectorCSSAgent.h
+++ b/Source/core/inspector/InspectorCSSAgent.h
@@ -108,6 +108,7 @@ public:
     virtual void clearFrontend() OVERRIDE;
     virtual void discardAgent() OVERRIDE;
     virtual void restore() OVERRIDE;
+    virtual void flushPendingFrontendMessages() OVERRIDE;
     virtual void enable(ErrorString*, PassRefPtr<EnableCallback>) OVERRIDE;
     virtual void disable(ErrorString*) OVERRIDE;
     void reset();
@@ -118,8 +119,8 @@ public:
     void willMutateStyle();
     void didMutateStyle(CSSStyleDeclaration*, bool);
 
-public:
     void activeStyleSheetsUpdated(Document*);
+    void documentDetached(Document*);
     void frameDetachedFromParent(LocalFrame*);
 
     virtual void getComputedStyleForNode(ErrorString*, int nodeId, RefPtr<TypeBuilder::Array<TypeBuilder::CSS::CSSComputedStyleProperty> >&) OVERRIDE;
@@ -159,8 +160,8 @@ private:
     void collectAllDocumentStyleSheets(Document*, Vector<CSSStyleSheet*>&);
     void collectStyleSheets(CSSStyleSheet*, Vector<CSSStyleSheet*>&);
 
-    void updateActiveStyleSheetsForDocument(Document*, StyleSheetsUpdateType);
-    void updateActiveStyleSheets(LocalFrame*, const Vector<CSSStyleSheet*>&, StyleSheetsUpdateType);
+    void updateActiveStyleSheets(Document*, StyleSheetsUpdateType);
+    void setActiveStyleSheets(Document*, const Vector<CSSStyleSheet*>&, StyleSheetsUpdateType);
 
     void collectPlatformFontsForRenderer(RenderText*, HashCountedSet<String>*);
 
@@ -194,7 +195,9 @@ private:
 
     IdToInspectorStyleSheet m_idToInspectorStyleSheet;
     HashMap<CSSStyleSheet*, RefPtr<InspectorStyleSheet> > m_cssStyleSheetToInspectorStyleSheet;
-    HashMap<LocalFrame*, OwnPtr<HashSet<CSSStyleSheet*> > > m_frameToCSSStyleSheets;
+    typedef HashMap<Document*, OwnPtr<HashSet<CSSStyleSheet*> > > DocumentStyleSheets;
+    DocumentStyleSheets m_documentToCSSStyleSheets;
+    HashSet<Document*> m_invalidatedDocuments;
 
     NodeToInspectorStyleSheet m_nodeToInspectorStyleSheet;
     HashMap<RefPtr<Document>, RefPtr<InspectorStyleSheet> > m_documentToViaInspectorStyleSheet; // "via inspector" stylesheets