Add a WebDocument::watchCssSelectors(selectors)

Source/core/dom/CSSSelectorWatch.h

+/*
+ * Copyright (C) 2013 Google Inc. All rights reserved.
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+ */
+
+#ifndef CSSSelectorWatch_h
+#define CSSSelectorWatch_h
+
+#include "core/css/StyleRule.h"
+#include "core/platform/Supplementable.h"
+#include "core/platform/Timer.h"
+#include "wtf/HashSet.h"
+#include "wtf/RefPtr.h"
+#include "wtf/Vector.h"
+#include "wtf/WeakPtr.h"
+#include "wtf/text/WTFString.h"
+
+namespace WebCore {
+
+class Document;
+class ScriptExecutionContext;
+
+class CSSSelectorWatch : public Supplement<ScriptExecutionContext> {
+public:
+    virtual ~CSSSelectorWatch() { }
+
+    static CSSSelectorWatch* from(Document*);
+
+    void watchCSSSelectors(const Vector<String>& selectors);
+    const Vector<RefPtr<StyleRule> >& watchedCallbackSelectors() const { return m_watchedCallbackSelectors; }
+
+    void addSelectorMatches(const Vector<String>& selectors);
+    void removeSelectorMatches(const Vector<String>& selectors);
+
+private:
+    CSSSelectorWatch(Document*);
+
+    void restartTimer();
+
+    // Runs FrameLoaderClient::selectorMatchChanged with the updated value of
+    // m_callbackSelectorChange.

[esprehn, 2013/09/04 06:08:28]

I'd leave off this comment. You don't need to describe the impl. :)

[Jeffrey Yasskin, 2013/09/12 22:09:59]

Done.

+    void callbackSelectorChangeTimerFired(Timer<CSSSelectorWatch>*);
+
+    Document* const m_document;

[esprehn, 2013/09/04 06:08:28]

We almost never do const like this... I suppose it's okay though.

[Jeffrey Yasskin, 2013/09/12 22:09:59]

It looks like in some places you're migrating to Document& instead of Document*
for things you know aren't NULL. I'll use that here too.

+
+    Vector<RefPtr<StyleRule> > m_watchedCallbackSelectors;
+
+    // Maps a CSS selector string with a -webkit-callback property to the number
+    // of matching RenderStyle objects in this document.
+    HashMap<String, int> m_matchingCallbackSelectors;
+    // Selectors are relative to m_matchingCallbackSelectors's contents at
+    // the previous call to selectorMatchChanged.
+    HashSet<String> m_addedSelectors;
+    HashSet<String> m_removedSelectors;
+
+    Timer<CSSSelectorWatch> m_callbackSelectorChangeTimer;
+
+    // When an element is reparented, the new location's style is evaluated after the expriation of the relayout timer.
+    // We don't want to send redundant callbacks to the embedder, so this counter lets us wait another time around the event loop.
+    int m_timerExpirations;
+};
+
+} // namespace WebCore
+
+#endif // CSSSelectorWatch_h