Implement declarativeContent API.

chrome/browser/extensions/extension_action.h

Index: chrome/browser/extensions/extension_action.h
diff --git a/chrome/browser/extensions/extension_action.h b/chrome/browser/extensions/extension_action.h
index dacd961ee03bb531df0289fc9037730a03071ccf..6b8f37bb1fd1bef6c1be2787ad86d5a8ba475345 100644
--- a/chrome/browser/extensions/extension_action.h
+++ b/chrome/browser/extensions/extension_action.h
@@ -220,15 +220,26 @@ class ExtensionAction {
   // care of any appropriate transition animations.  Returns true if
   // the appearance has changed.
   bool SetAppearance(int tab_id, Appearance value);
+  // The declarative appearance overrides a default appearance but is overridden
+  // by an appearance set directly on the tab.
+  void DeclarativeShow(int tab_id);
+  void UndoDeclarativeShow(int tab_id);
+
   // Get the badge visibility for a tab, or the default badge visibility
   // if none was set.
   bool GetIsVisible(int tab_id) const {
-    return GetValue(&appearance_, tab_id) != INVISIBLE;
+    return GetDeclarativeValue(&appearance_,
+                               &declarative_show_count_, ACTIVE,
+                               tab_id)
+        != INVISIBLE;
   }
 
   // True if the tab's action wants the user's attention.
   bool WantsAttention(int tab_id) const {
-    return GetValue(&appearance_, tab_id) == WANTS_ATTENTION;
+    return GetDeclarativeValue(&appearance_,
+                               &declarative_show_count_, ACTIVE,
+                               tab_id)
+        == WANTS_ATTENTION;
   }
 
   // Remove all tab-specific state.
@@ -283,6 +294,30 @@ class ExtensionAction {
     }
   }
 
+  // Returns the first of map[tab_id], declarative_map[tab_id] (uses
+  // |declarative_value|), map[kDefaultTabId], or ValueTraits<T>::CreateEmpty()

[battre, 2013/01/18 16:13:40]

I think the "declarative_map[tab_id] (uses |declarative_value|)" is difficult to
grasp.  Can you write more about the concept here? I don't understand why these
maps exist.

[Jeffrey Yasskin, 2013/01/22 08:01:22]

This function was too general anyway; I've rewritten it to just cover
appearance_. If more of these attributes acquire declarative control, I can
abstract out the function then.

Hopefully the new comment, and the comment before declarative_show_count_
explain why it exists?

[battre, 2013/01/22 12:54:52]

Beautiful!

+  // that's defined.  Don't return this result to an extension's background page
+  // because the declarative state can leak information about hosts the
+  // extension doesn't have permission to access.
+  template<class T>
+  T GetDeclarativeValue(const std::map<int, T>* map,
+                        const std::map<int, int>* declarative_map,
+                        T declarative_value,
+                        int tab_id) const {
+    typename std::map<int, T>::const_iterator iter = map->find(tab_id);
+    if (iter != map->end())
+      return iter->second;
+
+    if (ContainsKey(*declarative_map, tab_id))
+      return declarative_value;
+
+    iter = map->find(kDefaultTabId);
+    if (iter != map->end())
+      return iter->second;
+
+    return ValueTraits<T>::CreateEmpty();
+  }
+
   // The id for the extension this action belongs to (as defined in the
   // extension manifest).
   const std::string extension_id_;
@@ -299,6 +334,16 @@ class ExtensionAction {
   std::map<int, SkColor> badge_text_color_;
   std::map<int, Appearance> appearance_;
 
+  // Declarative state exists for two reasons: First, we need to hide it from
+  // the extension's background/event page to avoid leaking data from hosts the
+  // extension doesn't have permission to access.  Second, the action's state
+  // gets both reset and given its declarative values in response to a
+  // WebContentsObserver::DidNavigateMainFrame event, and there's no way to set
+  // those up to be called in the right order.
+
+  // Maps tab_id to the number of times

[battre, 2013/01/18 16:13:40]

nit: this sentence seems incomplete and lacks a ".".

[Jeffrey Yasskin, 2013/01/22 08:01:22]

That's not a nit. ;) Thanks; fixed.

+  std::map<int, int> declarative_show_count_;
+
   // IconAnimations are destroyed by a delayed task on the UI message loop so
   // that even if the Extension and ExtensionAction are destroyed on a non-UI
   // thread, the animation will still only be touched from the UI thread.  This