Reorder browser list on workspace switch

chrome/browser/ui/browser_list.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/browser_list.h"
 
 #include <algorithm>
 
 #include "base/auto_reset.h"
 #include "base/logging.h"
@@ skipping 168 matching lines @@
   } else if (!resetting_handlers) {
     base::AutoReset<bool> resetting_handlers_scoper(&resetting_handlers, true);
     for (BrowserVector::const_iterator it = browsers_to_close.begin();
          it != browsers_to_close.end(); ++it) {
       (*it)->ResetBeforeUnloadHandlers();
     }
   }
 }
 
 // static
+void BrowserList::ReorderAfterWorkspaceChange(
+    const std::string& new_workspace) {
+  DCHECK(!new_workspace.empty());
+
+  BrowserList* instance = GetInstance();
+
+  Browser* old_last_active = instance->GetLastActive();
+  BrowserVector& last_active_browsers = instance->last_active_browsers_;
+
+  // Perform a stable partition on the browsers in the list so that the browsers
+  // in the new workspace appear after the browsers in the other workspaces.
+  //
+  // For example, if we have a list of browser-workspace pairs
+  // [{b1, 0}, {b2, 1}, {b3, 0}, {b4, 1}]
+  // and we switch to workspace 1, we want the resulting browser list to look
+  // like [{b1, 0}, {b3, 0}, {b2, 1}, {b4, 1}].
+  BrowserVector in_this_workspace;

[sky, 2016/07/06 20:33:05]

Isn't this the same as a sort with a comparator that looks at workspace?

[Tom (Use chromium acct), 2016/07/06 22:29:16]

Nice catch.  stable_sort is much cleaner

+  BrowserVector in_different_workspace;
+  for (Browser* browser : last_active_browsers) {
+    if (browser->window()->GetWorkspace() == new_workspace)
+      in_this_workspace.push_back(browser);
+    else
+      in_different_workspace.push_back(browser);
+  }
+  last_active_browsers.clear();
+  last_active_browsers.insert(last_active_browsers.end(),
+                               in_different_workspace.begin(),
+                               in_different_workspace.end());
+  last_active_browsers.insert(last_active_browsers.end(),
+                               in_this_workspace.begin(),
+                               in_this_workspace.end());
+
+  Browser* new_last_active = instance->GetLastActive();
+  if (old_last_active != new_last_active) {
+    FOR_EACH_OBSERVER(chrome::BrowserListObserver, observers_.Get(),
+                      OnBrowserSetLastActive(new_last_active));
+  }
+}
+
+// static
 void BrowserList::SetLastActive(Browser* browser) {
   content::RecordAction(UserMetricsAction("ActiveBrowserChanged"));
 
   RemoveBrowserFrom(browser, &GetInstance()->last_active_browsers_);
   GetInstance()->last_active_browsers_.push_back(browser);
 
   FOR_EACH_OBSERVER(chrome::BrowserListObserver, observers_.Get(),
                     OnBrowserSetLastActive(browser));
 }
 
@@ skipping 27 matching lines @@
 }
 
 // static
 void BrowserList::RemoveBrowserFrom(Browser* browser,
                                     BrowserVector* browser_list) {
   BrowserVector::iterator remove_browser =
       std::find(browser_list->begin(), browser_list->end(), browser);
   if (remove_browser != browser_list->end())
     browser_list->erase(remove_browser);
 }