Add the android partner bookmark shim.

chrome/browser/android/partner_bookmarks_shim.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_ANDROID_PARTNER_BOOKMARKS_SHIM_H_
+#define CHROME_BROWSER_ANDROID_PARTNER_BOOKMARKS_SHIM_H_
+
+#include "base/android/jni_helper.h"
+#include "base/memory/scoped_ptr.h"
+#include "chrome/browser/bookmarks/bookmark_model.h"
+
+// A shim that lives on top of a BookmarkModel that allows the injection of
+// Partner bookmarks without submitting changes to the user configured bookmark
+// model.
+// Partner bookmarks folder is pseudo-injected as a subfolder to "attach node".
+// Because we cannot modify the BookmarkModel, the following needs to
+// be done on a client side:
+// 1. bookmark_node->is_root() -> shim->IsRootNode(bookmark_node)
+// 2. bookmark_node->parent() -> shim->GetParentOf(bookmark_node)
+// 3. bookmark_model->GetNodeByID(id) -> shim->GetNodeByID(id)
+class PartnerBookmarksShim {
+ public:
+  // The mask used to determining if an ID is a partner bookmark.  When
+  // constructing partner bookmarks, ensure the IDs are based on this value.
+  static const int64 kPartnerBookmarkIdBits;

[sky, 2012/08/09 15:48:19]

How do you know that a valid bookmark can't end up with this id?

[Ted C, 2012/08/09 16:47:01]

@Ruslan, any reason you chose this number originally?

If not, is there any part of the ID space that is assured to never have
bookmarks?  Does the model use any negative IDs?

[sky, 2012/08/09 19:41:11]

We don't restrict the ids in anyway.

+
+  // Returns the active instance of the shim.
+  static PartnerBookmarksShim* GetInstance();

[sky, 2012/08/09 15:48:19]

constructor/destructor before other methods.

[Ted C, 2012/08/09 16:47:01]

Done.

+
+  // Constructor is public for LazyInstance; DON'T CALL; use ::GetInstance().
+  PartnerBookmarksShim();
+  // Destructor is public for LazyInstance;
+  ~PartnerBookmarksShim();
+  void Reset();

[sky, 2012/08/09 15:48:19]

Add documentation.

[Ted C, 2012/08/09 16:47:01]

Done.

+
+  // Pseudo-injects partner bookmarks (if any) under the "attach_node".
+  void AttachTo(BookmarkModel* bookmark_model,

[sky, 2012/08/09 15:48:19]

I think this class should be a profilekeyedservice and be attached to a specific
bookmarkmodel. Much less error prone that way.

[Ted C, 2012/08/09 16:47:01]

will look into that next.

+                const BookmarkNode* attach_node);
+  // Returns true if everything got loaded and attached
+  bool IsLoaded() const;
+  // Returns true if there are partner bookmarks
+  bool HasPartnerBookmarks() const;
+
+  // For "Loaded" and "ShimBeingDeleted" notifications
+  struct Observer {

[sky, 2012/08/09 15:48:19]

This should be a class.

[Ted C, 2012/08/09 16:47:01]

Done.

+    // Called when everything is loaded and attached
+    virtual void PartnerShimLoaded(PartnerBookmarksShim*) {}
+    // Called just before everything got destroyed
+    virtual void ShimBeingDeleted(PartnerBookmarksShim*) {}
+   protected:
+    virtual ~Observer() {}
+  };
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
+  // Replacements for BookmarkModel/BookmarkNode methods
+  static bool IsBookmarkEditable(const BookmarkNode* node);
+  bool IsRootNode(const BookmarkNode* node) const;
+  const BookmarkNode* GetNodeByID(int64 id) const;
+  const BookmarkNode* GetParentOf(const BookmarkNode* node) const;
+  const BookmarkNode* GetAttachPoint() const { return attach_point_; }

[sky, 2012/08/09 15:48:19]

Trivial accessors should be named used unix_hacker_style.

[Ted C, 2012/08/09 16:47:01]

Done.

+  static bool IsPartnerBookmarkId(int64 id);
+  const BookmarkNode* GetPartnerBookmarksRoot() const;
+  // Sets the root node of the partner bookmarks and notifies any observers that
+  // the shim has now been loaded.  Takes ownership of |root_node|.
+  void SetPartnerBookmarksRoot(BookmarkNode* root_node);
+
+ private:
+  const BookmarkNode* GetNodeByID(const BookmarkNode* parent, int64 id) const;
+
+  scoped_ptr<BookmarkNode> partner_bookmarks_root_;
+  BookmarkModel* bookmark_model_;
+  const BookmarkNode* attach_point_;
+  bool loaded_;  // Set only on UI thread
+
+  // The observers.
+  ObserverList<Observer> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(PartnerBookmarksShim);
+};
+
+#endif  // CHROME_BROWSER_ANDROID_PARTNER_BOOKMARKS_SHIM_H_