Make installed_loader UMA less wasteful.

extensions/common/manifest.h

 // Copyright 2013 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 EXTENSIONS_COMMON_MANIFEST_H_
 #define EXTENSIONS_COMMON_MANIFEST_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 21 matching lines @@
                         // registry on Windows).
     UNPACKED,           // From loading an unpacked extension from the
                         // extensions settings page.
     COMPONENT,          // An integral component of Chrome itself, which
                         // happens to be implemented as an extension. We don't
                         // show these in the management UI.
     EXTERNAL_PREF_DOWNLOAD,    // A crx file from an external directory (via
                                // prefs), installed from an update URL.
     EXTERNAL_POLICY_DOWNLOAD,  // A crx file from an external directory (via
                                // admin policies), installed from an update URL.
-    COMMAND_LINE,       // --load-extension.
-    EXTERNAL_POLICY,    // A crx file from an external directory (via admin
-                        // policies), cached locally and installed from the
-                        // cache.
-    EXTERNAL_COMPONENT, // Similar to COMPONENT in that it's considered an
-                        // internal implementation detail of chrome, but
-                        // installed from an update URL like the *DOWNLOAD ones.
+    COMMAND_LINE,              // --load-extension.
+    EXTERNAL_POLICY,     // A crx file from an external directory (via admin
+                         // policies), cached locally and installed from the
+                         // cache.
+    EXTERNAL_COMPONENT,  // Similar to COMPONENT in that it's considered an
+                         // internal implementation detail of chrome, but
+    // installed from an update URL like the *DOWNLOAD ones.
 
+    // New enum values must go above here.
     NUM_LOCATIONS
   };
 
   // Do not change the order of entries or remove entries in this list
   // as this is used in UMA_HISTOGRAM_ENUMERATIONs about extensions.
   enum Type {
     TYPE_UNKNOWN = 0,
     TYPE_EXTENSION,
     TYPE_THEME,
     TYPE_USER_SCRIPT,
     TYPE_HOSTED_APP,
     // This is marked legacy because platform apps are preferred. For
     // backwards compatibility, we can't remove support for packaged apps
     TYPE_LEGACY_PACKAGED_APP,
     TYPE_PLATFORM_APP,
-    TYPE_SHARED_MODULE
+    TYPE_SHARED_MODULE,
+
+    // New enum values must go above here.
+    NUM_LOAD_TYPES
   };
 
   // Given two install sources, return the one which should take priority
   // over the other. If an extension is installed from two sources A and B,
   // its install source should be set to GetHigherPriorityLocation(A, B).
   static Location GetHigherPriorityLocation(Location loc1, Location loc2);
 
   // Whether the |location| is external or not.
   static inline bool IsExternalLocation(Location location) {
     return location == EXTERNAL_PREF ||
@@ skipping 113 matching lines @@
   scoped_ptr<base::DictionaryValue> value_;
 
   Type type_;
 
   DISALLOW_COPY_AND_ASSIGN(Manifest);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_MANIFEST_H_