Site Settings Desktop: Implement individual cookie removal and RemoveAll.

chrome/browser/browsing_data/cookies_tree_model.cc

 // 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.
 
 #include "chrome/browser/browsing_data/cookies_tree_model.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <functional>
@@ skipping 1507 matching lines @@
 }
 
 void CookiesTreeModel::MaybeNotifyBatchesEnded() {
   // Only notify the observers if this is the outermost call to EndBatch() if
   // called in a nested manner.
   if (batches_ended_ == batches_started_ &&
       batches_seen_ == batches_expected_) {
     FOR_EACH_OBSERVER(Observer,
                       cookies_observer_list_,
                       TreeModelEndBatch(this));
+    SetBatchExpectation(0, true);

[Finnur, 2016/08/17 16:55:54]

This is an augmentation of the fix I submitted here:
https://codereview.chromium.org/863503002/

The problem I encountered was when showing the cookie data list. It starts off a
batch of number of batches. Once it ends, batches_started_ and batches_ended_
match and are non-zero. All good up till then.

But once I select RemoveAll cookies, it starts a new batch but because
batches_started > 0, it doesn't fire off TreeModelBeginBatch because of line
1508 above. It does, however, fire TreeModelEndBatch (line 1527), which confuses
the clients (they DCHECK on batches ending that haven't been started).

If I null out the counters when the final batch has ended, this problem doesn't
happen.

[Finnur, 2016/08/17 16:58:54]

Second paragraph should have read:

   }
 }