Discardable property support on TabManager

chrome/browser/memory/tab_manager.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/memory/tab_manager.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <set>
@@ skipping 599 matching lines @@
     return false;
 
   // Do not discard a recently used tab.
   if (minimum_protection_time_.InSeconds() > 0) {
     auto delta =
         NowTicks() - GetWebContentsData(web_contents)->LastInactiveTime();
     if (delta < minimum_protection_time_)
       return false;
   }
 
+  // Do not discard a tab that was explicitly disallowed to.
+  if (!IsTabAutoDiscardable(web_contents))
+    return false;
+
   return true;
 }
 
 WebContents* TabManager::DiscardWebContentsAt(int index, TabStripModel* model) {
   // Can't discard active index.
   if (model->active_index() == index)
     return nullptr;
 
   WebContents* old_contents = model->GetWebContentsAt(index);
 
@@ skipping 91 matching lines @@
   web_contents_data->set_test_tick_clock(test_tick_clock_);
   return web_contents_data;
 }
 
 // static
 bool TabManager::CompareTabStats(TabStats first, TabStats second) {
   // Being currently selected is most important to protect.
   if (first.is_selected != second.is_selected)
     return first.is_selected;
 
+  // Non auto-discardable tabs are more important to protect.
+  if (first.is_auto_discardable != second.is_auto_discardable)
+    return !first.is_auto_discardable;
+
   // Protect tabs with pending form entries.
   if (first.has_form_entry != second.has_form_entry)
     return first.has_form_entry;
 
   // Protect streaming audio and video conferencing tabs as these are similar to
   // active tabs.
   if (first.is_media != second.is_media)
     return first.is_media;
 
   // Tab with internal web UI like NTP or Settings are good choices to discard,
@@ skipping 158 matching lines @@
 void TabManager::RemoveObserver(TabManagerObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
 void TabManager::OnDiscardedStateChange(content::WebContents* contents,
                                         bool is_discarded) {
   FOR_EACH_OBSERVER(TabManagerObserver, observers_,
                     OnDiscardedStateChange(contents, is_discarded));
 }
 
+void TabManager::OnAutoDiscardableStateChange(content::WebContents* contents,
+                                              bool is_auto_discardable) {
+  FOR_EACH_OBSERVER(
+      TabManagerObserver, observers_,
+      OnAutoDiscardableStateChange(contents, is_auto_discardable));
+}
+
+bool TabManager::IsTabAutoDiscardable(content::WebContents* contents) const {
+  return GetWebContentsData(contents)->IsAutoDiscardable();
+}
+
+void TabManager::SetTabAutoDiscardableState(content::WebContents* contents,
+                                            bool state) {
+  GetWebContentsData(contents)->SetAutoDiscardableState(state);
+}
+
 }  // namespace memory