Cleanup: Pass std::string as const reference if possible

chrome/browser/extensions/api/identity/identity_apitest.cc

 // Copyright (c) 2012 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.
 
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/prefs/pref_service.h"
@@ skipping 378 matching lines @@
   scoped_ptr<OAuth2MintTokenFlow> flow_;
 
   std::string login_access_token_;
 };
 
 class MockQueuedMintRequest : public IdentityMintRequestQueue::Request {
  public:
   MOCK_METHOD1(StartMintToken, void(IdentityMintRequestQueue::MintType));
 };
 
-gaia::AccountIds CreateIds(std::string email, std::string obfid) {
+gaia::AccountIds CreateIds(const std::string& email, const std::string& obfid) {
   gaia::AccountIds ids;
   ids.account_key = email;
   ids.email = email;
   ids.gaia = obfid;
   return ids;
 }
 
 class IdentityGetAccountsFunctionTest : public ExtensionBrowserTest {
   void SetUpCommandLine(base::CommandLine* command_line) override {
     ExtensionBrowserTest::SetUpCommandLine(command_line);
@@ skipping 253 matching lines @@
   EXPECT_TRUE(info->id.empty());
 }
 
 class GetAuthTokenFunctionTest : public IdentityTestWithSignin {
  public:
   void SetUpCommandLine(base::CommandLine* command_line) override {
     IdentityTestWithSignin::SetUpCommandLine(command_line);
     command_line->AppendSwitch(switches::kExtensionsMultiAccount);
   }
 
-  void IssueLoginRefreshTokenForAccount(const std::string account_key) {
+  void IssueLoginRefreshTokenForAccount(const std::string& account_key) {
     token_service_->UpdateCredentials(account_key, "refresh_token");
   }
 
-  void IssueLoginAccessTokenForAccount(const std::string account_key) {
+  void IssueLoginAccessTokenForAccount(const std::string& account_key) {
     token_service_->IssueAllTokensForAccount(
         account_key,
         "access_token-" + account_key,
         base::Time::Now() + base::TimeDelta::FromSeconds(3600));
   }
 
   void SetAccountState(gaia::AccountIds ids, bool is_signed_in) {
     IdentityAPI::GetFactoryInstance()->Get(profile())->SetAccountStateForTest(
         ids, is_signed_in);
   }
@@ skipping 43 matching lines @@
     SigninManagerBase* signin_manager =
         SigninManagerFactory::GetForProfile(browser()->profile());
     return signin_manager->GetAuthenticatedAccountId();
   }
 
   void SetCachedToken(const IdentityTokenCacheValue& token_data) {
     ExtensionTokenKey key(extension_id_, GetPrimaryAccountId(), oauth_scopes_);
     id_api()->SetCachedToken(key, token_data);
   }
 
-  const IdentityTokenCacheValue& GetCachedToken(std::string account_id) {
-    if (account_id.empty())
-      account_id = GetPrimaryAccountId();
-    ExtensionTokenKey key(extension_id_, account_id, oauth_scopes_);
+  const IdentityTokenCacheValue& GetCachedToken(const std::string& account_id) {
+    ExtensionTokenKey key(
+        extension_id_, account_id.empty() ? GetPrimaryAccountId() : account_id,
+        oauth_scopes_);
     return id_api()->GetCachedToken(key);
   }
 
   void QueueRequestStart(IdentityMintRequestQueue::MintType type,
                          IdentityMintRequestQueue::Request* request) {
     ExtensionTokenKey key(extension_id_, GetPrimaryAccountId(), oauth_scopes_);
     id_api()->mint_queue()->RequestStart(type, key, request);
   }
 
   void QueueRequestComplete(IdentityMintRequestQueue::MintType type,
@@ skipping 1082 matching lines @@
   EXPECT_EQ(std::string("https://abcdefghij.chromiumapp.org/callback#test"),
             url);
 }
 
 }  // namespace extensions
 
 // Tests the chrome.identity API implemented by custom JS bindings .
 IN_PROC_BROWSER_TEST_F(ExtensionApiTest, ChromeIdentityJsBindings) {
   ASSERT_TRUE(RunExtensionTest("identity/js_bindings")) << message_;
 }