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

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

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@193020 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 36 insertions, 36 deletions

diff --git a/components/autofill/browser/phone_number_i18n_unittest.cc b/components/autofill/browser/phone_number_i18n_unittest.cc
index 7744272..0547520 100644
--- a/components/autofill/browser/phone_number_i18n_unittest.cc
+++ b/components/autofill/browser/phone_number_i18n_unittest.cc
@@ -337,7 +337,7 @@ TEST(PhoneNumberI18NTest, PhoneNumbersMatch) {
   // Same numbers, undefined country code.
   EXPECT_TRUE(PhoneNumbersMatch(ASCIIToUTF16("4158889999"),
                                 ASCIIToUTF16("4158889999"),
-                                "",
+                                std::string(),
                                 "en-US"));
 
   // Numbers differ by country code only.
diff --git a/components/autofill/browser/wallet/full_wallet_unittest.cc b/components/autofill/browser/wallet/full_wallet_unittest.cc
index 9eead30..5a65940 100644
--- a/components/autofill/browser/wallet/full_wallet_unittest.cc
+++ b/components/autofill/browser/wallet/full_wallet_unittest.cc
@@ -402,8 +402,8 @@ TEST_F(FullWalletTest, CreateFullWalletWithRequiredActions) {
 
   FullWallet full_wallet(-1,
                          -1,
-                         "",
-                         "",
+                         std::string(),
+                         std::string(),
                          scoped_ptr<Address>(),
                          scoped_ptr<Address>(),
                          required_actions);
@@ -411,14 +411,13 @@ TEST_F(FullWalletTest, CreateFullWalletWithRequiredActions) {
 
   ASSERT_FALSE(required_actions.empty());
   required_actions.pop_back();
-  FullWallet different_required_actions(
-      -1,
-      -1,
-      "",
-      "",
-      scoped_ptr<Address>(),
-      scoped_ptr<Address>(),
-      required_actions);
+  FullWallet different_required_actions(-1,
+                                        -1,
+                                        std::string(),
+                                        std::string(),
+                                        scoped_ptr<Address>(),
+                                        scoped_ptr<Address>(),
+                                        required_actions);
   EXPECT_NE(full_wallet, different_required_actions);
 }
 
diff --git a/components/autofill/browser/wallet/wallet_address_unittest.cc b/components/autofill/browser/wallet/wallet_address_unittest.cc
index 0949c6a..7ac92f7 100644
--- a/components/autofill/browser/wallet/wallet_address_unittest.cc
+++ b/components/autofill/browser/wallet/wallet_address_unittest.cc
@@ -176,7 +176,7 @@ TEST_F(WalletAddressTest, CreateAddressMissingObjectId) {
                   ASCIIToUTF16("administrative_area_name"),
                   ASCIIToUTF16("postal_code_number"),
                   ASCIIToUTF16("phone_number"),
-                  "");
+                  std::string());
   ASSERT_EQ(address, *Address::CreateAddress(*dict_));
 }
 
@@ -243,7 +243,7 @@ TEST_F(WalletAddressTest, CreateDisplayAddress) {
                   ASCIIToUTF16("state"),
                   ASCIIToUTF16("postal_code"),
                   ASCIIToUTF16("phone_number"),
-                  "");
+                  std::string());
   ASSERT_EQ(address, *Address::CreateDisplayAddress(*dict_));
 }
 
@@ -272,7 +272,7 @@ TEST_F(WalletAddressTest, ToDictionaryWithoutID) {
                   ASCIIToUTF16("administrative_area_name"),
                   ASCIIToUTF16("postal_code_number"),
                   ASCIIToUTF16("phone_number"),
-                  "");
+                  std::string());
 
   EXPECT_TRUE(expected.Equals(address.ToDictionaryWithoutID().get()));
 }
diff --git a/components/autofill/browser/wallet/wallet_client_unittest.cc b/components/autofill/browser/wallet/wallet_client_unittest.cc
index 27d1a2d..6229847 100644
--- a/components/autofill/browser/wallet/wallet_client_unittest.cc
+++ b/components/autofill/browser/wallet/wallet_client_unittest.cc
@@ -810,9 +810,8 @@ TEST_F(WalletClientTest, NetworkFailureOnExpectedVoidResponse) {
   delegate_.ExpectBaselineMetrics(NO_ESCROW_REQUEST, HAS_WALLET_REQUEST);
   delegate_.ExpectWalletErrorMetric(AutofillMetrics::WALLET_NETWORK_ERROR);
 
-  wallet_client_->SendAutocheckoutStatus(autofill::SUCCESS,
-                                         GURL(kMerchantUrl),
-                                         "");
+  wallet_client_->SendAutocheckoutStatus(
+      autofill::SUCCESS, GURL(kMerchantUrl), std::string());
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
   ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_UNAUTHORIZED);
@@ -840,9 +839,8 @@ TEST_F(WalletClientTest, RequestError) {
   delegate_.ExpectBaselineMetrics(NO_ESCROW_REQUEST, HAS_WALLET_REQUEST);
   delegate_.ExpectWalletErrorMetric(AutofillMetrics::WALLET_BAD_REQUEST);
 
-  wallet_client_->SendAutocheckoutStatus(autofill::SUCCESS,
-                                         GURL(kMerchantUrl),
-                                         "");
+  wallet_client_->SendAutocheckoutStatus(
+      autofill::SUCCESS, GURL(kMerchantUrl), std::string());
   net::TestURLFetcher* fetcher = factory_.GetFetcherByID(0);
   ASSERT_TRUE(fetcher);
   fetcher->set_response_code(net::HTTP_BAD_REQUEST);
diff --git a/components/autofill/browser/wallet/wallet_items_unittest.cc b/components/autofill/browser/wallet/wallet_items_unittest.cc
index 552a31b..9495d8b 100644
--- a/components/autofill/browser/wallet/wallet_items_unittest.cc
+++ b/components/autofill/browser/wallet/wallet_items_unittest.cc
@@ -418,7 +418,7 @@ TEST_F(WalletItemsTest, CreateMaskedInstrument) {
                                           ASCIIToUTF16("state"),
                                           ASCIIToUTF16("postal_code"),
                                           ASCIIToUTF16("phone_number"),
-                                          ""));
+                                          std::string()));
   std::vector<string16> supported_currencies;
   supported_currencies.push_back(ASCIIToUTF16("currency"));
   WalletItems::MaskedInstrument masked_instrument(
@@ -520,7 +520,7 @@ TEST_F(WalletItemsTest, CreateWalletItems) {
                                                   ASCIIToUTF16("state"),
                                                   ASCIIToUTF16("postal_code"),
                                                   ASCIIToUTF16("phone_number"),
-                                                  ""));
+                                                  std::string()));
   std::vector<string16> supported_currencies;
   supported_currencies.push_back(ASCIIToUTF16("currency"));
   scoped_ptr<WalletItems::MaskedInstrument> masked_instrument(
diff --git a/components/autofill/browser/wallet/wallet_signin_helper_unittest.cc b/components/autofill/browser/wallet/wallet_signin_helper_unittest.cc
index e574d55..20175b1 100644
--- a/components/autofill/browser/wallet/wallet_signin_helper_unittest.cc
+++ b/components/autofill/browser/wallet/wallet_signin_helper_unittest.cc
@@ -120,9 +120,10 @@ class WalletSigninHelperTest : public testing::Test {
 
   void MockFailedOAuthLoginResponse404() {
     SetUpFetcherResponseAndCompleteRequest(
-        GaiaUrls::GetInstance()->client_login_url(), 404,
+        GaiaUrls::GetInstance()->client_login_url(),
+        404,
         net::ResponseCookies(),
-        "");
+        std::string());
   }
 
   void MockSuccessfulGaiaUserInfoResponse(const std::string& username) {
@@ -134,9 +135,10 @@ class WalletSigninHelperTest : public testing::Test {
 
   void MockFailedGaiaUserInfoResponse404() {
     SetUpFetcherResponseAndCompleteRequest(
-        GaiaUrls::GetInstance()->get_user_info_url(), 404,
+        GaiaUrls::GetInstance()->get_user_info_url(),
+        404,
         net::ResponseCookies(),
-        "");
+        std::string());
   }
 
   void MockSuccessfulGetAccountInfoResponse(const std::string& username) {
@@ -150,23 +152,24 @@ class WalletSigninHelperTest : public testing::Test {
 
   void MockFailedGetAccountInfoResponse404() {
     SetUpFetcherResponseAndCompleteRequest(
-        signin_helper_->GetGetAccountInfoUrlForTesting(), 404,
+        signin_helper_->GetGetAccountInfoUrlForTesting(),
+        404,
         net::ResponseCookies(),
-        "");
+        std::string());
   }
 
   void MockSuccessfulPassiveAuthUrlMergeAndRedirectResponse() {
-    SetUpFetcherResponseAndCompleteRequest(
-        wallet::GetPassiveAuthUrl().spec(), 200,
-        net::ResponseCookies(),
-        "");
+    SetUpFetcherResponseAndCompleteRequest(wallet::GetPassiveAuthUrl().spec(),
+                                           200,
+                                           net::ResponseCookies(),
+                                           std::string());
   }
 
   void MockFailedPassiveAuthUrlMergeAndRedirectResponse404() {
-    SetUpFetcherResponseAndCompleteRequest(
-        wallet::GetPassiveAuthUrl().spec(), 404,
-        net::ResponseCookies(),
-        "");
+    SetUpFetcherResponseAndCompleteRequest(wallet::GetPassiveAuthUrl().spec(),
+                                           404,
+                                           net::ResponseCookies(),
+                                           std::string());
   }
 
   WalletSigninHelperForTesting::State state() const {