Rewrite std::string("") to std::string(), Linux edition.

This patch was generated by running the empty_string clang tool
across the Chromium Linux compilation database. Implicitly or
explicitly constructing std::string() with a "" argument is
inefficient as the caller needs to emit extra instructions to
pass an argument, and the constructor needlessly copies a byte
into internal storage. Rewriting these instances to simply call
the default constructor appears to save ~14-18 kilobytes on an
optimized release build.

BUG=none

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=193020

Review URL: https://codereview.chromium.org/13145003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@193040 0039d316-1c4b-4281-b951-d872f2087c98

11 files changed, 124 insertions, 105 deletions

diff --git a/google_apis/gaia/gaia_auth_fetcher.cc b/google_apis/gaia/gaia_auth_fetcher.cc
index 9354447..15aa78a 100644
--- a/google_apis/gaia/gaia_auth_fetcher.cc
+++ b/google_apis/gaia/gaia_auth_fetcher.cc
@@ -617,7 +617,7 @@ void GaiaAuthFetcher::StartClientLogin(
                                       allow_hosted_accounts);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   "",
+                                   std::string(),
                                    client_login_gurl_,
                                    kLoadFlagsIgnoreCookies,
                                    this));
@@ -635,7 +635,7 @@ void GaiaAuthFetcher::StartIssueAuthToken(const std::string& sid,
   request_body_ = MakeIssueAuthTokenBody(sid, lsid, service);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   "",
+                                   std::string(),
                                    issue_auth_token_gurl_,
                                    kLoadFlagsIgnoreCookies,
                                    this));
@@ -669,7 +669,7 @@ void GaiaAuthFetcher::StartRevokeOAuth2Token(const std::string& auth_token) {
   request_body_ = MakeRevokeTokenBody(auth_token);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   "",
+                                   std::string(),
                                    oauth2_revoke_gurl_,
                                    kLoadFlagsIgnoreCookies,
                                    this));
@@ -692,7 +692,7 @@ void GaiaAuthFetcher::StartCookieForOAuthLoginTokenExchange(
 
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   "",
+                                   std::string(),
                                    client_login_to_oauth2_gurl_,
                                    net::LOAD_NORMAL,
                                    this));
@@ -708,7 +708,7 @@ void GaiaAuthFetcher::StartAuthCodeForOAuth2TokenExchange(
   request_body_ = MakeGetTokenPairBody(auth_code);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   "",
+                                   std::string(),
                                    oauth2_token_gurl_,
                                    kLoadFlagsIgnoreCookies,
                                    this));
@@ -723,7 +723,7 @@ void GaiaAuthFetcher::StartGetUserInfo(const std::string& lsid) {
   request_body_ = MakeGetUserInfoBody(lsid);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   "",
+                                   std::string(),
                                    get_user_info_gurl_,
                                    kLoadFlagsIgnoreCookies,
                                    this));
@@ -748,7 +748,7 @@ void GaiaAuthFetcher::StartMergeSession(const std::string& uber_token) {
   request_body_ = MakeMergeSessionBody(uber_token, continue_url, source_);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   "",
+                                   std::string(),
                                    merge_session_gurl_,
                                    net::LOAD_NORMAL,
                                    this));
@@ -765,7 +765,7 @@ void GaiaAuthFetcher::StartTokenFetchForUberAuthExchange(
   std::string authentication_header =
       base::StringPrintf(kOAuthHeaderFormat, access_token.c_str());
   fetcher_.reset(CreateGaiaFetcher(getter_,
-                                   "",
+                                   std::string(),
                                    authentication_header,
                                    uberauth_token_gurl_,
                                    kLoadFlagsIgnoreCookies,
@@ -785,7 +785,7 @@ void GaiaAuthFetcher::StartClientOAuth(const std::string& username,
                                       source_, locale);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   "",
+                                   std::string(),
                                    client_oauth_gurl_,
                                    kLoadFlagsIgnoreCookies,
                                    this));
@@ -814,7 +814,7 @@ void GaiaAuthFetcher::StartClientOAuthChallengeResponse(
   request_body_ = MakeClientOAuthChallengeResponseBody(name, token, solution);
   fetcher_.reset(CreateGaiaFetcher(getter_,
                                    request_body_,
-                                   "",
+                                   std::string(),
                                    client_oauth_gurl_,
                                    kLoadFlagsIgnoreCookies,
                                    this));
diff --git a/google_apis/gaia/gaia_auth_fetcher_unittest.cc b/google_apis/gaia/gaia_auth_fetcher_unittest.cc
index 226ee1a..47b6d15 100644
--- a/google_apis/gaia/gaia_auth_fetcher_unittest.cc
+++ b/google_apis/gaia/gaia_auth_fetcher_unittest.cc
@@ -311,10 +311,10 @@ TEST_F(GaiaAuthFetcherTest, ParseRequest) {
   RunParsingTest("SID=sid\nLSID=lsid\nAuth=auth\n", "sid", "lsid", "auth");
   RunParsingTest("LSID=lsid\nSID=sid\nAuth=auth\n", "sid", "lsid", "auth");
   RunParsingTest("SID=sid\nLSID=lsid\nAuth=auth", "sid", "lsid", "auth");
-  RunParsingTest("SID=sid\nAuth=auth\n", "sid", "", "auth");
-  RunParsingTest("LSID=lsid\nAuth=auth\n", "", "lsid", "auth");
-  RunParsingTest("\nAuth=auth\n", "", "", "auth");
-  RunParsingTest("SID=sid", "sid", "", "");
+  RunParsingTest("SID=sid\nAuth=auth\n", "sid", std::string(), "auth");
+  RunParsingTest("LSID=lsid\nAuth=auth\n", std::string(), "lsid", "auth");
+  RunParsingTest("\nAuth=auth\n", std::string(), std::string(), "auth");
+  RunParsingTest("SID=sid", "sid", std::string(), std::string());
 }
 
 TEST_F(GaiaAuthFetcherTest, ParseErrorRequest) {
@@ -588,7 +588,11 @@ TEST_F(GaiaAuthFetcherTest, FullTokenFailure) {
   MockFetcher mock_fetcher(
       issue_auth_token_source_,
       net::URLRequestStatus(net::URLRequestStatus::SUCCESS, 0),
-      net::HTTP_FORBIDDEN, cookies_, "", net::URLFetcher::GET, &auth);
+      net::HTTP_FORBIDDEN,
+      cookies_,
+      std::string(),
+      net::URLFetcher::GET,
+      &auth);
   auth.OnURLFetchComplete(&mock_fetcher);
   EXPECT_FALSE(auth.HasPendingFetch());
 }
@@ -613,8 +617,11 @@ TEST_F(GaiaAuthFetcherTest, OAuthLoginTokenSuccess) {
   MockFetcher mock_fetcher1(
       client_login_to_oauth2_source_,
       net::URLRequestStatus(net::URLRequestStatus::SUCCESS, 0),
-      net::HTTP_OK, cookies, "",
-      net::URLFetcher::POST, &auth);
+      net::HTTP_OK,
+      cookies,
+      std::string(),
+      net::URLFetcher::POST,
+      &auth);
   auth.OnURLFetchComplete(&mock_fetcher1);
   EXPECT_TRUE(auth.HasPendingFetch());
   MockFetcher mock_fetcher2(
@@ -652,8 +659,11 @@ TEST_F(GaiaAuthFetcherTest, OAuthLoginTokenClientLoginToOAuth2Failure) {
   MockFetcher mock_fetcher(
       client_login_to_oauth2_source_,
       net::URLRequestStatus(net::URLRequestStatus::SUCCESS, 0),
-      net::HTTP_FORBIDDEN, cookies, "",
-      net::URLFetcher::POST, &auth);
+      net::HTTP_FORBIDDEN,
+      cookies,
+      std::string(),
+      net::URLFetcher::POST,
+      &auth);
   auth.OnURLFetchComplete(&mock_fetcher);
   EXPECT_FALSE(auth.HasPendingFetch());
 }
@@ -674,15 +684,21 @@ TEST_F(GaiaAuthFetcherTest, OAuthLoginTokenOAuth2TokenPairFailure) {
   MockFetcher mock_fetcher1(
       client_login_to_oauth2_source_,
       net::URLRequestStatus(net::URLRequestStatus::SUCCESS, 0),
-      net::HTTP_OK, cookies, "",
-      net::URLFetcher::POST, &auth);
+      net::HTTP_OK,
+      cookies,
+      std::string(),
+      net::URLFetcher::POST,
+      &auth);
   auth.OnURLFetchComplete(&mock_fetcher1);
   EXPECT_TRUE(auth.HasPendingFetch());
   MockFetcher mock_fetcher2(
       oauth2_token_source_,
       net::URLRequestStatus(net::URLRequestStatus::SUCCESS, 0),
-      net::HTTP_FORBIDDEN, cookies_, "",
-      net::URLFetcher::POST, &auth);
+      net::HTTP_FORBIDDEN,
+      cookies_,
+      std::string(),
+      net::URLFetcher::POST,
+      &auth);
   auth.OnURLFetchComplete(&mock_fetcher2);
   EXPECT_FALSE(auth.HasPendingFetch());
 }
@@ -810,7 +826,7 @@ TEST_F(GaiaAuthFetcherTest, ClientOAuthSuccess) {
   std::vector<std::string> scopes;
   scopes.push_back(GaiaUrls::GetInstance()->oauth1_login_scope());
   scopes.push_back("https://some.other.scope.com");
-  auth.StartClientOAuth("username", "password", scopes, "", "en");
+  auth.StartClientOAuth("username", "password", scopes, std::string(), "en");
 
   std::string expected_text = base::StringPrintf(
       "{"
@@ -842,7 +858,8 @@ TEST_F(GaiaAuthFetcherTest, ClientOAuthWithQuote) {
   GaiaAuthFetcher auth(&consumer, "te\"sts", profile_.GetRequestContext());
   std::vector<std::string> scopes;
   scopes.push_back("https://some.\"other.scope.com");
-  auth.StartClientOAuth("user\"name", "pass\"word", scopes, "", "e\"n");
+  auth.StartClientOAuth(
+      "user\"name", "pass\"word", scopes, std::string(), "e\"n");
 
   std::string expected_text = base::StringPrintf(
       "{"
@@ -879,7 +896,7 @@ TEST_F(GaiaAuthFetcherTest, ClientOAuthBadAuth) {
   GaiaAuthFetcher auth(&consumer, "tests", profile_.GetRequestContext());
   std::vector<std::string> scopes;
   scopes.push_back(GaiaUrls::GetInstance()->oauth1_login_scope());
-  auth.StartClientOAuth("username", "password", scopes, "", "en");
+  auth.StartClientOAuth("username", "password", scopes, std::string(), "en");
 }
 
 TEST_F(GaiaAuthFetcherTest, ClientOAuthCaptchaChallenge) {
@@ -908,7 +925,7 @@ TEST_F(GaiaAuthFetcherTest, ClientOAuthCaptchaChallenge) {
   GaiaAuthFetcher auth(&consumer, "tests", profile_.GetRequestContext());
   std::vector<std::string> scopes;
   scopes.push_back(GaiaUrls::GetInstance()->oauth1_login_scope());
-  auth.StartClientOAuth("username", "password", scopes, "", "en");
+  auth.StartClientOAuth("username", "password", scopes, std::string(), "en");
 }
 
 TEST_F(GaiaAuthFetcherTest, ClientOAuthTwoFactorChallenge) {
@@ -936,7 +953,7 @@ TEST_F(GaiaAuthFetcherTest, ClientOAuthTwoFactorChallenge) {
   GaiaAuthFetcher auth(&consumer, "tests", profile_.GetRequestContext());
   std::vector<std::string> scopes;
   scopes.push_back(GaiaUrls::GetInstance()->oauth1_login_scope());
-  auth.StartClientOAuth("username", "password", scopes, "", "en");
+  auth.StartClientOAuth("username", "password", scopes, std::string(), "en");
 }
 
 TEST_F(GaiaAuthFetcherTest, ClientOAuthChallengeSuccess) {
diff --git a/google_apis/gaia/google_service_auth_error.cc b/google_apis/gaia/google_service_auth_error.cc
index 8beeb4d..96fc063 100644
--- a/google_apis/gaia/google_service_auth_error.cc
+++ b/google_apis/gaia/google_service_auth_error.cc
@@ -225,7 +225,7 @@ DictionaryValue* GoogleServiceAuthError::ToValue() const {
 std::string GoogleServiceAuthError::ToString() const {
   switch (state_) {
     case NONE:
-      return "";
+      return std::string();
     case INVALID_GAIA_CREDENTIALS:
       return "Invalid credentials.";
     case USER_NOT_SIGNED_UP:
diff --git a/google_apis/gaia/google_service_auth_error_unittest.cc b/google_apis/gaia/google_service_auth_error_unittest.cc
index 59aa510..15155b6 100644
--- a/google_apis/gaia/google_service_auth_error_unittest.cc
+++ b/google_apis/gaia/google_service_auth_error_unittest.cc
@@ -64,7 +64,7 @@ TEST_F(GoogleServiceAuthErrorTest, CaptchaChallenge) {
   EXPECT_TRUE(value->GetDictionary("captcha", &captcha_value));
   ASSERT_TRUE(captcha_value);
   ExpectDictStringValue("captcha_token", *captcha_value, "token");
-  ExpectDictStringValue("", *captcha_value, "audioUrl");
+  ExpectDictStringValue(std::string(), *captcha_value, "audioUrl");
   ExpectDictStringValue("http://www.google.com/", *captcha_value, "imageUrl");
   ExpectDictStringValue("http://www.bing.com/", *captcha_value, "unlockUrl");
   ExpectDictIntegerValue(0, *captcha_value, "imageWidth");
diff --git a/google_apis/gaia/oauth2_access_token_fetcher_unittest.cc b/google_apis/gaia/oauth2_access_token_fetcher_unittest.cc
index feb8020..7c761c7 100644
--- a/google_apis/gaia/oauth2_access_token_fetcher_unittest.cc
+++ b/google_apis/gaia/oauth2_access_token_fetcher_unittest.cc
@@ -120,7 +120,7 @@ class OAuth2AccessTokenFetcherTest : public testing::Test {
 
 // These four tests time out, see http://crbug.com/113446.
 TEST_F(OAuth2AccessTokenFetcherTest, DISABLED_GetAccessTokenRequestFailure) {
-  TestURLFetcher* url_fetcher = SetupGetAccessToken(false, 0, "");
+  TestURLFetcher* url_fetcher = SetupGetAccessToken(false, 0, std::string());
   EXPECT_CALL(consumer_, OnGetTokenFailure(_)).Times(1);
   fetcher_.Start("client_id", "client_secret", "refresh_token", ScopeList());
   fetcher_.OnURLFetchComplete(url_fetcher);
@@ -129,7 +129,7 @@ TEST_F(OAuth2AccessTokenFetcherTest, DISABLED_GetAccessTokenRequestFailure) {
 TEST_F(OAuth2AccessTokenFetcherTest,
        DISABLED_GetAccessTokenResponseCodeFailure) {
   TestURLFetcher* url_fetcher =
-      SetupGetAccessToken(true, net::HTTP_FORBIDDEN, "");
+      SetupGetAccessToken(true, net::HTTP_FORBIDDEN, std::string());
   EXPECT_CALL(consumer_, OnGetTokenFailure(_)).Times(1);
   fetcher_.Start("client_id", "client_secret", "refresh_token", ScopeList());
   fetcher_.OnURLFetchComplete(url_fetcher);
diff --git a/google_apis/gaia/oauth2_api_call_flow_unittest.cc b/google_apis/gaia/oauth2_api_call_flow_unittest.cc
index 137eaeb..4e8692e 100644
--- a/google_apis/gaia/oauth2_api_call_flow_unittest.cc
+++ b/google_apis/gaia/oauth2_api_call_flow_unittest.cc
@@ -158,8 +158,8 @@ class OAuth2ApiCallFlowTest : public testing::Test {
     GURL url(CreateApiUrl());
     EXPECT_CALL(*flow_, CreateApiCallBody()).WillOnce(Return(body));
     EXPECT_CALL(*flow_, CreateApiCallUrl()).WillOnce(Return(url));
-    TestURLFetcher* url_fetcher = CreateURLFetcher(
-        url, succeeds, status, "");
+    TestURLFetcher* url_fetcher =
+        CreateURLFetcher(url, succeeds, status, std::string());
     EXPECT_CALL(factory_, CreateURLFetcher(_, url, _, _))
         .WillOnce(Return(url_fetcher));
     return url_fetcher;
@@ -240,7 +240,7 @@ TEST_F(OAuth2ApiCallFlowTest, EmptyAccessTokenFirstApiCallSucceeds) {
   std::string at = "access_token";
   std::vector<std::string> scopes(CreateTestScopes());
 
-  CreateFlow(rt, "", scopes);
+  CreateFlow(rt, std::string(), scopes);
   SetupAccessTokenFetcher(rt, scopes);
   TestURLFetcher* url_fetcher = SetupApiCall(true, net::HTTP_OK);
   EXPECT_CALL(*flow_, ProcessApiCallSuccess(url_fetcher));
@@ -256,7 +256,7 @@ TEST_F(OAuth2ApiCallFlowTest, EmptyAccessTokenApiCallFails) {
   std::string at = "access_token";
   std::vector<std::string> scopes(CreateTestScopes());
 
-  CreateFlow(rt, "", scopes);
+  CreateFlow(rt, std::string(), scopes);
   SetupAccessTokenFetcher(rt, scopes);
   TestURLFetcher* url_fetcher = SetupApiCall(false, net::HTTP_BAD_GATEWAY);
   EXPECT_CALL(*flow_, ProcessApiCallFailure(url_fetcher));
@@ -272,7 +272,7 @@ TEST_F(OAuth2ApiCallFlowTest, EmptyAccessTokenNewTokenGenerationFails) {
   std::string at = "access_token";
   std::vector<std::string> scopes(CreateTestScopes());
 
-  CreateFlow(rt, "", scopes);
+  CreateFlow(rt, std::string(), scopes);
   SetupAccessTokenFetcher(rt, scopes);
   GoogleServiceAuthError error(
       GoogleServiceAuthError::INVALID_GAIA_CREDENTIALS);
diff --git a/google_apis/gaia/oauth2_mint_token_flow.cc b/google_apis/gaia/oauth2_mint_token_flow.cc
index 42fc4ef..169d187 100644
--- a/google_apis/gaia/oauth2_mint_token_flow.cc
+++ b/google_apis/gaia/oauth2_mint_token_flow.cc
@@ -89,17 +89,16 @@ OAuth2MintTokenFlow::Parameters::Parameters(
 
 OAuth2MintTokenFlow::Parameters::~Parameters() {}
 
-OAuth2MintTokenFlow::OAuth2MintTokenFlow(
-    URLRequestContextGetter* context,
-    Delegate* delegate,
-    const Parameters& parameters)
-    : OAuth2ApiCallFlow(
-          context, parameters.login_refresh_token,
-          "", std::vector<std::string>()),
+OAuth2MintTokenFlow::OAuth2MintTokenFlow(URLRequestContextGetter* context,
+                                         Delegate* delegate,
+                                         const Parameters& parameters)
+    : OAuth2ApiCallFlow(context,
+                        parameters.login_refresh_token,
+                        std::string(),
+                        std::vector<std::string>()),
       delegate_(delegate),
       parameters_(parameters),
-      ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)) {
-}
+      ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)) {}
 
 OAuth2MintTokenFlow::~OAuth2MintTokenFlow() { }
 
diff --git a/google_apis/gaia/oauth2_mint_token_flow_unittest.cc b/google_apis/gaia/oauth2_mint_token_flow_unittest.cc
index e213984..3206601 100644
--- a/google_apis/gaia/oauth2_mint_token_flow_unittest.cc
+++ b/google_apis/gaia/oauth2_mint_token_flow_unittest.cc
@@ -272,7 +272,7 @@ TEST_F(OAuth2MintTokenFlowTest, ParseIssueAdviceResponse) {
 TEST_F(OAuth2MintTokenFlowTest, ProcessApiCallSuccess) {
   {  // No body.
     TestURLFetcher url_fetcher(1, GURL("http://www.google.com"), NULL);
-    url_fetcher.SetResponseString("");
+    url_fetcher.SetResponseString(std::string());
     CreateFlow(OAuth2MintTokenFlow::MODE_MINT_TOKEN_NO_FORCE);
     EXPECT_CALL(delegate_, OnMintTokenFailure(_));
     flow_->ProcessApiCallSuccess(&url_fetcher);
diff --git a/google_apis/gaia/oauth_request_signer.cc b/google_apis/gaia/oauth_request_signer.cc
index b5d138f..9952a6f 100644
--- a/google_apis/gaia/oauth_request_signer.cc
+++ b/google_apis/gaia/oauth_request_signer.cc
@@ -89,7 +89,7 @@ std::string BuildBaseString(const GURL& request_base_url,
 
 std::string BuildBaseStringParameters(
     const OAuthRequestSigner::Parameters& parameters) {
-  std::string result = "";
+  std::string result;
   OAuthRequestSigner::Parameters::const_iterator cursor;
   OAuthRequestSigner::Parameters::const_iterator limit;
   bool first = true;
@@ -297,7 +297,7 @@ bool SignParameters(const GURL& request_base_url,
 // static
 bool OAuthRequestSigner::Decode(const std::string& text,
                                 std::string* decoded_text) {
-  std::string accumulator = "";
+  std::string accumulator;
   std::string::const_iterator cursor;
   std::string::const_iterator limit;
   for (limit = text.end(), cursor = text.begin(); cursor != limit; ++cursor) {
@@ -335,7 +335,7 @@ bool OAuthRequestSigner::Decode(const std::string& text,
 
 // static
 std::string OAuthRequestSigner::Encode(const std::string& text) {
-  std::string result = "";
+  std::string result;
   std::string::const_iterator cursor;
   std::string::const_iterator limit;
   for (limit = text.end(), cursor = text.begin(); cursor != limit; ++cursor) {
diff --git a/google_apis/gaia/oauth_request_signer_unittest.cc b/google_apis/gaia/oauth_request_signer_unittest.cc
index 5cf2dc2..40206f6 100644
--- a/google_apis/gaia/oauth_request_signer_unittest.cc
+++ b/google_apis/gaia/oauth_request_signer_unittest.cc
@@ -109,15 +109,15 @@ TEST(OAuthRequestSignerTest, SignGet2) {
   parameters["oauth_nonce"] = "4d4hZW9DygWQujP2tz06UN";
   std::string signed_text;
   ASSERT_TRUE(OAuthRequestSigner::SignURL(
-                  request_url,
-                  parameters,
-                  OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
-                  OAuthRequestSigner::GET_METHOD,
-                  "anonymous",  // oauth_consumer_key
-                  "anonymous",  // consumer secret
-                  "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
-                  "", // token secret
-                  &signed_text));
+      request_url,
+      parameters,
+      OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
+      OAuthRequestSigner::GET_METHOD,
+      "anonymous",                       // oauth_consumer_key
+      "anonymous",                       // consumer secret
+      "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
+      std::string(),                     // token secret
+      &signed_text));
   ASSERT_EQ(signed_text,
             "https://accounts.google.com/OAuthGetAccessToken"
             "?oauth_consumer_key=anonymous"
@@ -137,14 +137,14 @@ TEST(OAuthRequestSignerTest, ParseAndSignGet1) {
                    "&oauth_timestamp=1308152953");
   std::string signed_text;
   ASSERT_TRUE(OAuthRequestSigner::ParseAndSign(
-                  request_url,
-                  OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
-                  OAuthRequestSigner::GET_METHOD,
-                  "anonymous",  // oauth_consumer_key
-                  "anonymous",  // consumer secret
-                  "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
-                  "", // token secret
-                  &signed_text));
+      request_url,
+      OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
+      OAuthRequestSigner::GET_METHOD,
+      "anonymous",                       // oauth_consumer_key
+      "anonymous",                       // consumer secret
+      "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
+      std::string(),                     // token secret
+      &signed_text));
   ASSERT_EQ("https://www.google.com/accounts/o8/GetOAuthToken"
             "?oauth_consumer_key=anonymous"
             "&oauth_nonce=2oiE_aHdk5qRTz0L9C8Lq0g"
@@ -164,14 +164,14 @@ TEST(OAuthRequestSignerTest, ParseAndSignGet2) {
                    "&oauth_nonce=4d4hZW9DygWQujP2tz06UN");
   std::string signed_text;
   ASSERT_TRUE(OAuthRequestSigner::ParseAndSign(
-                  request_url,
-                  OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
-                  OAuthRequestSigner::GET_METHOD,
-                  "anonymous",  // oauth_consumer_key
-                  "anonymous",  // consumer secret
-                  "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
-                  "", // token secret
-                  &signed_text));
+      request_url,
+      OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
+      OAuthRequestSigner::GET_METHOD,
+      "anonymous",                       // oauth_consumer_key
+      "anonymous",                       // consumer secret
+      "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
+      std::string(),                     // token secret
+      &signed_text));
   ASSERT_EQ(signed_text,
             "https://accounts.google.com/OAuthGetAccessToken"
             "?oauth_consumer_key=anonymous"
@@ -220,15 +220,15 @@ TEST(OAuthRequestSignerTest, SignPost2) {
   parameters["oauth_nonce"] = "17171717171717171";
   std::string signed_text;
   ASSERT_TRUE(OAuthRequestSigner::SignURL(
-                  request_url,
-                  parameters,
-                  OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
-                  OAuthRequestSigner::POST_METHOD,
-                  "anonymous",  // oauth_consumer_key
-                  "anonymous",  // consumer secret
-                  "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
-                  "", // token secret
-                  &signed_text));
+      request_url,
+      parameters,
+      OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
+      OAuthRequestSigner::POST_METHOD,
+      "anonymous",                       // oauth_consumer_key
+      "anonymous",                       // consumer secret
+      "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
+      std::string(),                     // token secret
+      &signed_text));
   ASSERT_EQ(signed_text,
             "oauth_consumer_key=anonymous"
             "&oauth_nonce=17171717171717171"
@@ -273,14 +273,14 @@ TEST(OAuthRequestSignerTest, ParseAndSignPost2) {
                    "&oauth_nonce=17171717171717171");
   std::string signed_text;
   ASSERT_TRUE(OAuthRequestSigner::ParseAndSign(
-                  request_url,
-                  OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
-                  OAuthRequestSigner::POST_METHOD,
-                  "anonymous",  // oauth_consumer_key
-                  "anonymous",  // consumer secret
-                  "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
-                  "", // token secret
-                  &signed_text));
+      request_url,
+      OAuthRequestSigner::HMAC_SHA1_SIGNATURE,
+      OAuthRequestSigner::POST_METHOD,
+      "anonymous",                       // oauth_consumer_key
+      "anonymous",                       // consumer secret
+      "4/CcC-hgdj1TNnWaX8NTQ76YDXCBEK",  // oauth_token
+      std::string(),                     // token secret
+      &signed_text));
   ASSERT_EQ(signed_text,
             "oauth_consumer_key=anonymous"
             "&oauth_nonce=17171717171717171"
diff --git a/google_apis/google_api_keys.cc b/google_apis/google_api_keys.cc
index cd13b9e..c05435e 100644
--- a/google_apis/google_api_keys.cc
+++ b/google_apis/google_api_keys.cc
@@ -98,22 +98,25 @@ class APIKeyCache {
 
     api_key_ = CalculateKeyValue(GOOGLE_API_KEY,
                                  STRINGIZE_NO_EXPANSION(GOOGLE_API_KEY),
-                                 NULL, "",
+                                 NULL,
+                                 std::string(),
                                  environment.get(),
                                  command_line);
 
-    std::string default_client_id = CalculateKeyValue(
-        GOOGLE_DEFAULT_CLIENT_ID,
-        STRINGIZE_NO_EXPANSION(GOOGLE_DEFAULT_CLIENT_ID),
-        NULL, "",
-        environment.get(),
-        command_line);
-    std::string default_client_secret = CalculateKeyValue(
-        GOOGLE_DEFAULT_CLIENT_SECRET,
-        STRINGIZE_NO_EXPANSION(GOOGLE_DEFAULT_CLIENT_SECRET),
-        NULL, "",
-        environment.get(),
-        command_line);
+    std::string default_client_id =
+        CalculateKeyValue(GOOGLE_DEFAULT_CLIENT_ID,
+                          STRINGIZE_NO_EXPANSION(GOOGLE_DEFAULT_CLIENT_ID),
+                          NULL,
+                          std::string(),
+                          environment.get(),
+                          command_line);
+    std::string default_client_secret =
+        CalculateKeyValue(GOOGLE_DEFAULT_CLIENT_SECRET,
+                          STRINGIZE_NO_EXPANSION(GOOGLE_DEFAULT_CLIENT_SECRET),
+                          NULL,
+                          std::string(),
+                          environment.get(),
+                          command_line);
 
     // We currently only allow overriding the baked-in values for the
     // default OAuth2 client ID and secret using a command-line