Add "UninstallReason" parameter to ExtensionRegistryObserver::OnExtensionUninstalled.

extensions/common/extension.h

Index: extensions/common/extension.h
diff --git a/extensions/common/extension.h b/extensions/common/extension.h
index 933c47ce09d8cba6259a7468206621793c6cc55d..fc1ff34c579ce9a02dafe5cc2dac14c7646c62bf 100644
--- a/extensions/common/extension.h
+++ b/extensions/common/extension.h
@@ -543,6 +543,32 @@ struct UnloadedExtensionInfo {
   UnloadedExtensionInfo(const Extension* extension, Reason reason);
 };
 
+struct UninstalledExtensionInfo {
+  enum Reason {
+    REASON_FOR_TESTING,         // Used for testing code only
+    REASON_USER_INITIATED,      // User performed some UI gesture
+    REASON_EXTENSION_DISABLED,  // Extension disabled due to error
+    REASON_STORAGE_THRESHOLD_EXCEEDED,
+    REASON_INSTALL_CANCELED,
+    REASON_MANAGEMENT_API,
+    REASON_SYNC,
+    REASON_ORPHANED_THEME,
+    REASON_ORPHANED_EPHEMERAL_EXTENSION,
+    // The entries below imply bypassing checking user has permission to
+    // uninstall the corresponding extension id.
+    REASON_ORPHANED_EXTERNAL_EXTENSION,
+    REASON_ORPHANED_SHARED_MODULE,
+    REASON_INTERNAL_MANAGEMENT  // Internal extensions (see usages)
+  };
+
+  Reason reason;
+
+  // The extension being uninstalled - this should always be non-NULL.
+  const Extension* extension;
+
+  UninstalledExtensionInfo(const Extension* extension, Reason reason);
+};
+
 // The details sent for EXTENSION_PERMISSIONS_UPDATED notifications.
 struct UpdatedExtensionPermissionsInfo {
   enum Reason {