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_
+
+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 {

[boliu, 2012/12/29 01:48:12]

style question: HistoryService inherits VisitedLinkDelegate. This URLEnumerator
class are sometimes referred to as HistoryService::URLEnumerator (in old code)
and VisitedLinkDelegate::URLEnumerator (new code in this patch).

Is there any convention that should be followed here?

[joth, 2012/12/29 18:32:06]

I don't know about any specific convention, but I find the latter more obvious
as it immediately tells me where to look to find the inner class definition.

[boliu, 2012/12/30 02:08:15]

Changed to VisitedLinkDelegate::URLEnumerator everywhere. Only one that might be
controversial is HistoryBackend::IterateURLs (which should probably be re-named
in a CL afterwards)

+   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 has been returned successfully.

[joth, 2012/12/29 18:32:06]

nit: has -> have

[boliu, 2012/12/30 02:08:15]

Done.

+    virtual void OnComplete(bool success) = 0;
+
+   protected:
+    virtual ~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.
+  virtual void RebuildTable(URLEnumerator* enumerator) = 0;
+
+ protected:
+  virtual ~VisitedLinkDelegate() {}
+};
+
+#endif  // CHROME_BROWSER_VISITEDLINK_VISITEDLINK_DELEGATE_H_