Implementing TabManager extensions API Discard Function.

chrome/browser/memory/tab_manager.cc

Index: chrome/browser/memory/tab_manager.cc
diff --git a/chrome/browser/memory/tab_manager.cc b/chrome/browser/memory/tab_manager.cc
index 6fa39ad66f4abcae4e9a2b8fd9c2677945db888f..1f98857d2d195fa48faaa6eb5b34667f7de30772 100644
--- a/chrome/browser/memory/tab_manager.cc
+++ b/chrome/browser/memory/tab_manager.cc
@@ -294,6 +294,13 @@ WebContents* TabManager::DiscardTabById(int64_t target_web_contents_id) {
   return DiscardWebContentsAt(index, model);
 }
 
+WebContents* TabManager::DiscardTabByExtension(content::WebContents* contents) {
+  if (contents)
+    return DiscardTabById(reinterpret_cast<int64_t>(contents));
+
+  return DiscardTabImpl();
+}
+
 void TabManager::LogMemoryAndDiscardTab() {
   LogMemory("Tab Discards Memory details",
             base::Bind(&TabManager::PurgeMemoryAndDiscardTab));
@@ -832,21 +839,23 @@ void TabManager::DoChildProcessDispatch() {
 // TODO(jamescook): This should consider tabs with references to other tabs,
 // such as tabs created with JavaScript window.open(). Potentially consider
 // discarding the entire set together, or use that in the priority computation.
-bool TabManager::DiscardTabImpl() {
+content::WebContents* TabManager::DiscardTabImpl() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   TabStatsList stats = GetTabStats();
 
   if (stats.empty())
-    return false;
+    return nullptr;
   // Loop until a non-discarded tab to kill is found.
   for (TabStatsList::const_reverse_iterator stats_rit = stats.rbegin();
        stats_rit != stats.rend(); ++stats_rit) {
     int64_t least_important_tab_id = stats_rit->tab_contents_id;
-    if (CanDiscardTab(least_important_tab_id) &&
-        DiscardTabById(least_important_tab_id))
-      return true;
+    if (CanDiscardTab(least_important_tab_id)) {
+      WebContents* new_contents = DiscardTabById(least_important_tab_id);
+      if (new_contents)
+        return new_contents;
+    }
   }
-  return false;
+  return nullptr;
 }
 
 // Check the variation parameter to see if a tab can be discarded only once or
@@ -906,4 +915,9 @@ void TabManager::OnDiscardedStateChange(content::WebContents* contents,
                     OnDiscardedStateChange(contents, is_discarded));
 }
 
+void TabManager::set_minimum_protection_time_for_tests(
+    unsigned int time_seconds) {
+  minimum_protection_time_ = base::TimeDelta::FromSeconds(time_seconds);
+}
+
 }  // namespace memory