Remove VisitedLink dependency on rest of chrome

chrome/browser/visitedlink/visitedlink_delegate.h

+// Copyright (c) 2012 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 CHROME_BROWSER_VISITEDLINK_VISITEDLINK_DELEGATE_H_
+#define CHROME_BROWSER_VISITEDLINK_VISITEDLINK_DELEGATE_H_
+
+#include "base/memory/ref_counted.h"
+
+class GURL;
+
+namespace content {
+class BrowserContext;
+}  // namespace content
+
+// Delegate class that clients of VisitedLinkMaster must implement.
+class VisitedLinkDelegate {
+ public:
+  // Returns true when the two BrowserContexts are equivalent.
+  virtual bool AreEquivalentContexts(content::BrowserContext* context1,
+                                     content::BrowserContext* context2) = 0;
+
+  // See RebuildTable.
+  class URLEnumerator : public base::RefCountedThreadSafe<URLEnumerator> {
+   public:
+    // Call this with each URL to rebuild the table.
+    virtual void OnURL(const GURL& url) = 0;
+
+    // This must be called by Delegate after RebuildTable is called. |success|
+    // indicates all URLs have been returned successfully. The URLEnumerator
+    // object cannot be used by the delegate after this call.
+    virtual void OnComplete(bool success) = 0;
+
+   protected:
+    virtual ~URLEnumerator() {}
+
+   private:
+    friend class base::RefCountedThreadSafe<URLEnumerator>;
+  };
+
+  // Delegate class is responsible for persisting the list of visited URLs
+  // across browser runs. This is called by VisitedLinkMaster to repopulate
+  // its internal table. Note that methods on enumerator can be called on any
+  // thread but the delegate is responsible for synchronizating the calls.
+  virtual void RebuildTable(const scoped_refptr<URLEnumerator>& enumerator) = 0;
+
+ protected:
+
+  virtual ~VisitedLinkDelegate() {}
+};
+
+#endif  // CHROME_BROWSER_VISITEDLINK_VISITEDLINK_DELEGATE_H_