Add setting to isolate zoom changes by default.

chrome/browser/ui/tabs/tab_strip_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/ui/tabs/tab_strip_model.h"
 
 #include <algorithm>
 #include <map>
 #include <set>
 #include <string>
@@ skipping 324 matching lines @@
                                                  WebContents* new_contents) {
   delegate_->WillAddWebContents(new_contents);
 
   DCHECK(ContainsIndex(index));
   WebContents* old_contents = GetWebContentsAtImpl(index);
 
   FixOpenersAndGroupsReferencing(index);
 
   contents_data_[index]->SetWebContents(new_contents);
 
+  old_contents->OnReplaced(new_contents);

[wjmaclean, 2017/01/19 21:09:05]

Can we perhaps re-name this to something like CloneZoomSettings()? Or have the
tab-strip do the cloning (if it can see the zoom controller, it could contact it
directly?)?

[Kevin McNee, 2017/01/25 23:42:56]

Done.

The zoom controller is now notified directly.

+
   for (auto& observer : observers_)
     observer.TabReplacedAt(this, old_contents, new_contents, index);
 
   // When the active WebContents is replaced send out a selection notification
   // too. We do this as nearly all observers need to treat a replacement of the
   // selected contents as the selection changing.
   if (active_index() == index) {
     for (auto& observer : observers_)
       observer.ActiveTabChanged(old_contents, new_contents, active_index(),
                                 TabStripModelObserver::CHANGE_REASON_REPLACED);
@@ skipping 1007 matching lines @@
 
 void TabStripModel::FixOpenersAndGroupsReferencing(int index) {
   WebContents* old_contents = GetWebContentsAtImpl(index);
   for (auto& data : contents_data_) {
     if (data->group() == old_contents)
       data->set_group(contents_data_[index]->group());
     if (data->opener() == old_contents)
       data->set_opener(contents_data_[index]->opener());
   }
 }