Add a WebDocument::watchCssSelectors(selectors)

public/web/WebDocument.h

Index: public/web/WebDocument.h
diff --git a/public/web/WebDocument.h b/public/web/WebDocument.h
index 23d107cacfc568da4ce6996a1636c16fe3a62724..bd98692faf681fa8f7d6cbe645095ac4a2601ecd 100644
--- a/public/web/WebDocument.h
+++ b/public/web/WebDocument.h
@@ -134,6 +134,11 @@ public:
     // WebView.
     BLINK_EXPORT void insertUserStyleSheet(const WebString& sourceCode, UserStyleLevel);
 
+    // Arranges to call WebFrameClient::didMatchCSS(frame(), ...) when one of
+    // the selectors matches or stops matching an element in this document.
+    // Each call to this method overrides any previous calls.
+    BLINK_EXPORT void watchCSSSelectors(const WebVector<WebString>& selectors);
+
     BLINK_EXPORT WebVector<WebDraggableRegion> draggableRegions() const;
 
     BLINK_EXPORT v8::Handle<v8::Value> registerEmbedderCustomElement(const WebString& name, v8::Handle<v8::Value> options, WebExceptionCode&);