Add the "file_handlers" manifest key for platform apps to replace "intents".

chrome/common/extensions/extension.h

Index: chrome/common/extensions/extension.h
diff --git a/chrome/common/extensions/extension.h b/chrome/common/extensions/extension.h
index 2ac6083b32411e928d0c678ccd1c3f0f7b8958ba..623a76c65b9189c2f4846720e03f9a363773cdc4 100644
--- a/chrome/common/extensions/extension.h
+++ b/chrome/common/extensions/extension.h
@@ -895,6 +895,10 @@ class Extension : public base::RefCountedThreadSafe<Extension> {
                            const base::DictionaryValue& intent_service,
                            string16* error);
   bool LoadWebIntentServices(string16* error);
+  bool LoadFileHandler(const std::string& handler_id,
+                       const base::DictionaryValue& handler_info,
+                       string16* error);
+  bool LoadFileHandlers(string16* error);
   bool LoadExtensionFeatures(const APIPermissionSet& api_permissions,
                              string16* error);
   bool LoadDevToolsPage(string16* error);