Apply automatic range checks to enum types across IPC.

chrome/common/search_provider.h

Index: chrome/common/search_provider.h
diff --git a/chrome/common/search_provider.h b/chrome/common/search_provider.h
index d55416c6c6bdf55129c63f7ecd7d32b6ba8af2c0..9b51df930e9dba2ccc28d40178900429fda229a8 100644
--- a/chrome/common/search_provider.h
+++ b/chrome/common/search_provider.h
@@ -33,7 +33,9 @@ enum InstallState {
   INSTALLED_BUT_NOT_DEFAULT = 1,
 
   // The search provider is set as the user's default.
-  INSTALLED_AS_DEFAULT = 2
+  INSTALLED_AS_DEFAULT = 2,
+
+  INSTALLED_STATE_LAST = INSTALLED_AS_DEFAULT
 };
 
 }  // namespace search_provider