Retry icon fetching after intent_helper is ready

components/arc/intent_helper/activity_icon_loader.h

 // Copyright 2016 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.
 
 #ifndef COMPONENTS_ARC_INTENT_HELPER_ACTIVITY_ICON_LOADER_H_
 #define COMPONENTS_ARC_INTENT_HELPER_ACTIVITY_ICON_LOADER_H_
 
 #include <map>
 #include <memory>
 #include <string>
@@ skipping 26 matching lines @@
 
     // TODO(yusukes): Add const to these variables later. At this point,
     // doing so seems to confuse g++ 4.6 on builders.
     std::string package_name;
 
     // Can be empty. When |activity_name| is empty, the loader tries to fetch
     // the package's default icon.
     std::string activity_name;
   };
 
+  enum class GetResult {
+    // Succeeded. The callback will be called asynchronously.
+    SUCCEEDED_ASYNC,
+    // Succeeded. The callback has already been called synchronously.
+    SUCCEEDED_SYNC,
+    // Failed. The intent_helper instance is not yet ready. This is a temporary
+    // error.
+    FAILED_ARC_NOT_READY,
+    // Failed. Either ARC is not supported at all or intent_helper instance
+    // version is too old.
+    FAILED_ARC_NOT_SUPPORTED,
+  };
+
   using ActivityToIconsMap = std::map<ActivityName, Icons>;
   using OnIconsReadyCallback =
       base::Callback<void(std::unique_ptr<ActivityToIconsMap>)>;
 
   ActivityIconLoader();
 
   // Removes icons associated with |package_name| from the cache.
   void InvalidateIcons(const std::string& package_name);
 
   // Retrieves icons for the |activities| and calls |cb|. The |cb| is called
   // back exactly once, either synchronously in the GetActivityIcons() when
   // all icons were already cached locally, or asynchronously with icons fetched
   // from ARC side.
-  // Returns true in the former synchronous case, where everything is done.
-  bool GetActivityIcons(const std::vector<ActivityName>& activities,
-                        const OnIconsReadyCallback& cb);
+  GetResult GetActivityIcons(const std::vector<ActivityName>& activities,
+                             const OnIconsReadyCallback& cb);
 
   void OnIconsResizedForTesting(const OnIconsReadyCallback& cb,
                                 std::unique_ptr<ActivityToIconsMap> result);
   void AddIconToCacheForTesting(const ActivityName& activity,
                                 const gfx::Image& image);
 
   const ActivityToIconsMap& cached_icons_for_testing() { return cached_icons_; }
 
  private:
   friend class base::RefCounted<ActivityIconLoader>;
@@ skipping 20 matching lines @@
   ActivityToIconsMap cached_icons_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(ActivityIconLoader);
 };
 
 }  // namespace arc
 
 #endif  // COMPONENTS_ARC_INTENT_HELPER_ACTIVITY_ICON_LOADER_H_