Discardable property support on TabManager

chrome/browser/memory/tab_manager.h

Index: chrome/browser/memory/tab_manager.h
diff --git a/chrome/browser/memory/tab_manager.h b/chrome/browser/memory/tab_manager.h
index cd5c3480417bf76976c8a3849ae4d0e5fe6c5057..fb1dba0d786a453639bc4ed8d9581dac46209634 100644
--- a/chrome/browser/memory/tab_manager.h
+++ b/chrome/browser/memory/tab_manager.h
@@ -128,6 +128,12 @@ class TabManager : public TabStripModelObserver {
   void AddObserver(TabManagerObserver* observer);
   void RemoveObserver(TabManagerObserver* observer);
 
+  // Returns true if the tab is auto discardable by auto discarding feature.

[Georges Khalil, 2016/07/22 15:07:57]

nit: reword the comment

Returns the auto discardable state of the tab. When true, the tab is eligible to
be automatically discarded when critical memory pressure hits, otherwise the tab
is ignored and will never be automatically discarded. Note that this property
doesn't block the discarding of the tab via other methods (about:discards for
instance).

[Anderson Silva, 2016/07/22 15:34:51]

Done.

+  bool IsTabAutoDiscardable(content::WebContents* contents) const;
+
+  // Sets/clears the AutoDiscardable state of the tab.
+  void SetTabAutoDiscardableState(content::WebContents* contents, bool state);

[Georges Khalil, 2016/07/22 15:07:57]

nit: s/AutoDiscardable/auto discardable

[Anderson Silva, 2016/07/22 15:34:51]

Done.

+
  private:
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest, CanOnlyDiscardOnce);
   FRIEND_TEST_ALL_PREFIXES(TabManagerTest, ChildProcessNotifications);
@@ -151,6 +157,12 @@ class TabManager : public TabStripModelObserver {
   void OnDiscardedStateChange(content::WebContents* contents,
                               bool is_discarded);
 
+  // Called by WebContentsData whenever the AutoDiscardable state of a
+  // WebContents

[Georges Khalil, 2016/07/22 15:07:57]

nit: line ending.
nit: s/AutoDiscardable/auto discardable

[Anderson Silva, 2016/07/22 15:34:51]

Done.

+  // changes, so that observers can be informed.
+  void OnAutoDiscardableStateChange(content::WebContents* contents,
+                                    bool is_auto_discardable);
+
   // The time that a renderer is given to react to a memory pressure
   // notification before another renderer is also notified. This prevents all
   // renderers from receiving and acting upon notifications simultaneously,