Add "UninstallReason" parameter to ExtensionRegistryObserver::OnExtensionUninstalled.

extensions/browser/uninstall_reason.h

Index: extensions/browser/uninstall_reason.h
diff --git a/extensions/browser/uninstall_reason.h b/extensions/browser/uninstall_reason.h
new file mode 100644
index 0000000000000000000000000000000000000000..728d47c8809f371ea997c8f0f55ae94c1b508144
--- /dev/null
+++ b/extensions/browser/uninstall_reason.h
@@ -0,0 +1,29 @@
+// Copyright 2014 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_BROWSER_UNINSTALL_REASON_H_
+#define EXTENSIONS_BROWSER_UNINSTALL_REASON_H_
+
+namespace extensions {
+
+enum UninstallReason {
+  UNINSTALL_REASON_FOR_TESTING,         // Used for testing code only
+  UNINSTALL_REASON_USER_INITIATED,      // User performed some UI gesture
+  UNINSTALL_REASON_EXTENSION_DISABLED,  // Extension disabled due to error
+  UNINSTALL_REASON_STORAGE_THRESHOLD_EXCEEDED,
+  UNINSTALL_REASON_INSTALL_CANCELED,
+  UNINSTALL_REASON_MANAGEMENT_API,
+  UNINSTALL_REASON_SYNC,
+  UNINSTALL_REASON_ORPHANED_THEME,
+  UNINSTALL_REASON_ORPHANED_EPHEMERAL_EXTENSION,
+  // The entries below imply bypassing checking user has permission to
+  // uninstall the corresponding extension id.
+  UNINSTALL_REASON_ORPHANED_EXTERNAL_EXTENSION,
+  UNINSTALL_REASON_ORPHANED_SHARED_MODULE,
+  UNINSTALL_REASON_INTERNAL_MANAGEMENT  // Internal extensions (see usages)
+};
+
+}  // extensions
+
+#endif  // EXTENSIONS_BROWSER_UNINSTALL_REASON_H_