Fix testInstallExtensions by adding correct crx files.

chrome/test/webdriver/commands/create_session.cc

Index: chrome/test/webdriver/commands/create_session.cc
diff --git a/chrome/test/webdriver/commands/create_session.cc b/chrome/test/webdriver/commands/create_session.cc
index a81986881bd3e31fc3faf415b6a427a0768f016d..9e73e3060db61ee88502d03b8b2f0cb53f7b9e56 100644
--- a/chrome/test/webdriver/commands/create_session.cc
+++ b/chrome/test/webdriver/commands/create_session.cc
@@ -161,7 +161,7 @@ void CreateSession::ExecutePost(Response* const response) {
       }
       FilePath extension_file(
           extensions_dir.path().AppendASCII("extension" +
-                                            base::IntToString(i)));
+                                            base::IntToString(i) + ".crx"));
       std::string message;
       if (!WriteBase64DataToFile(extension_file, base64_extension, &message)) {
         response->SetError(new Error(kBadRequest, message));