Cleanup: Pass std::string as const reference from components/

Passing std::string by reference can prevent extra copying of object.

BUG=367418
TEST=
R=blundell@chromium.org,jochen@chromium.org,sdefresne@chromium.org

Review URL: https://codereview.chromium.org/1355983002

Cr-Commit-Position: refs/heads/master@{#351023}

components/cdm/renderer/widevine_key_systems.cc

@@ -20,7 +20,7 @@ using media::SupportedCodecs;
 namespace cdm {
 
 // Return |name|'s parent key system.
-static std::string GetDirectParentName(std::string name) {
+static std::string GetDirectParentName(const std::string& name) {
   size_t last_period = name.find_last_of('.');
   DCHECK_GT(last_period, 0u);
   return name.substr(0u, last_period);

components/certificate_transparency/log_proof_fetcher_unittest.cc

@@ -98,11 +98,11 @@ class GetSTHResponseHandler : public net::URLRequestInterceptor {
     return job;
   }
 
-  void set_response_body(std::string response_body) {
+  void set_response_body(const std::string& response_body) {
     response_body_ = response_body;
   }
 
-  void set_response_headers(std::string response_headers) {
+  void set_response_headers(const std::string& response_headers) {
     response_headers_ = response_headers;
   }
 

components/data_reduction_proxy/core/browser/data_reduction_proxy_bypass_protocol_unittest.cc

@@ -259,7 +259,7 @@ class DataReductionProxyProtocolTest : public testing::Test {
   }
 
   // Returns the key to the |ProxyRetryInfoMap|.
-  std::string GetProxyKey(std::string proxy) {
+  std::string GetProxyKey(const std::string& proxy) {
     net::ProxyServer proxy_server = net::ProxyServer::FromURI(
         proxy, net::ProxyServer::SCHEME_HTTP);
     if (!proxy_server.is_valid())

components/data_reduction_proxy/core/browser/data_reduction_proxy_config_unittest.cc

@@ -310,7 +310,7 @@ TEST_F(DataReductionProxyConfigTest,
   CheckSecureProxyCheckOnIPChange("OK", SUCCEEDED_PROXY_ENABLED, false, false);
 }
 
-std::string GetRetryMapKeyFromOrigin(std::string origin) {
+std::string GetRetryMapKeyFromOrigin(const std::string& origin) {
   // The retry map has the scheme prefix for https but not for http.
   return origin;
 }

components/dom_distiller/core/dom_distiller_store_unittest.cc

@@ -79,8 +79,10 @@ class FakeSyncChangeProcessor : public syncer::SyncChangeProcessor {
   EntryMap* model_;
 };
 
-ArticleEntry CreateEntry(std::string entry_id, std::string page_url1,
-                         std::string page_url2, std::string page_url3) {
+ArticleEntry CreateEntry(const std::string& entry_id,
+                         const std::string& page_url1,
+                         const std::string& page_url2,
+                         const std::string& page_url3) {
   ArticleEntry entry;
   entry.set_entry_id(entry_id);
   if (!page_url1.empty()) {

components/dom_distiller/core/url_utils_unittest.cc

@@ -41,12 +41,12 @@ TEST(DomDistillerUrlUtilsTest, TestGetValueForKeyInUrlPathQuery) {
   EXPECT_EQ("foo", GetValueForKeyInUrlPathQuery(valid_url_two_keys, "key"));
 }
 
-std::string ThroughDistiller(std::string url) {
+std::string ThroughDistiller(const std::string& url) {
   return GetOriginalUrlFromDistillerUrl(
       GetDistillerViewUrlFromUrl(kDomDistillerScheme, GURL(url))).spec();
 }
 
-std::string GetOriginalUrlFromDistillerUrl(std::string url) {
+std::string GetOriginalUrlFromDistillerUrl(const std::string& url) {
   return GetOriginalUrlFromDistillerUrl(GURL(url)).spec();
 }
 

components/gcm_driver/gcm_account_tracker_unittest.cc

@@ -24,11 +24,11 @@ namespace {
 const char kAccountId1[] = "account_1";
 const char kAccountId2[] = "account_2";
 
-std::string AccountKeyToObfuscatedId(const std::string email) {
+std::string AccountKeyToObfuscatedId(const std::string& email) {
   return "obfid-" + email;
 }
 
-std::string GetValidTokenInfoResponse(const std::string account_key) {
+std::string GetValidTokenInfoResponse(const std::string& account_key) {
   return std::string("{ \"id\": \"") + AccountKeyToObfuscatedId(account_key) +
          "\" }";
 }

components/invalidation/impl/gcm_network_channel_unittest.cc

@@ -170,8 +170,7 @@ class GCMNetworkChannelTest
     last_invalidator_state_ = invalidator_state;
   }
 
-  void OnIncomingMessage(std::string incoming_message) {
-  }
+  void OnIncomingMessage(std::string /* incoming_message */) {}
 
   GCMNetworkChannel* network_channel() {
     return gcm_network_channel_.get();

components/metrics/cloned_install_detector.cc

@@ -65,7 +65,7 @@ void ClonedInstallDetector::CheckForClonedInstall(
 }
 
 void ClonedInstallDetector::SaveMachineId(PrefService* local_state,
-                                          std::string raw_id) {
+                                          const std::string& raw_id) {
   if (raw_id.empty()) {
     LogMachineIdState(ID_GENERATION_FAILED);
     local_state->ClearPref(prefs::kMetricsMachineId);

components/metrics/cloned_install_detector.h

@@ -46,7 +46,7 @@ class ClonedInstallDetector {
   // Converts raw_id into a 24-bit hash and stores the hash in |local_state|.
   // |raw_id| is not a const ref because it's passed from a cross-thread post
   // task.
-  void SaveMachineId(PrefService* local_state, std::string raw_id);
+  void SaveMachineId(PrefService* local_state, const std::string& raw_id);
 
   scoped_refptr<MachineIdProvider> raw_id_provider_;
   base::WeakPtrFactory<ClonedInstallDetector> weak_ptr_factory_;

components/network_hints/renderer/dns_prefetch_queue.h

@@ -63,7 +63,7 @@ class DnsQueue {
   // Returns true for success, false for failure (nothing written).
   PushResult Push(const char* source, const size_t length);
 
-  PushResult Push(std::string source) {
+  PushResult Push(const std::string& source) {
     return Push(source.c_str(), source.length());
   }
 

components/password_manager/core/browser/login_database_unittest.cc

@@ -1371,7 +1371,8 @@ class LoginDatabaseMigrationTest : public testing::TestWithParam<int> {
   // Returns an empty vector on failure. Otherwise returns values in the column
   // |column_name| of the logins table. The order of the
   // returned rows is well-defined.
-  template <class T> std::vector<T> GetValues(std::string column_name) {
+  template <class T>
+  std::vector<T> GetValues(const std::string& column_name) {
     sql::Connection db;
     std::vector<T> results;
     if (!db.Open(database_path_))

components/proximity_auth/ble/bluetooth_low_energy_connection_finder.cc

@@ -314,7 +314,7 @@ void BluetoothLowEnergyConnectionFinder::RestartDiscoverySessionWhenReady() {
 }
 
 BluetoothDevice* BluetoothLowEnergyConnectionFinder::GetDevice(
-    std::string device_address) {
+    const std::string& device_address) {
   // It's not possible to simply use
   // |adapter_->GetDevice(GetRemoteDeviceAddress())| to find the device with MAC
   // address |GetRemoteDeviceAddress()|. For paired devices,

components/proximity_auth/ble/bluetooth_low_energy_connection_finder.h

@@ -126,7 +126,7 @@ class BluetoothLowEnergyConnectionFinder
   void InvokeCallbackAsync();
 
   // Returns the device with |device_address|.
-  device::BluetoothDevice* GetDevice(std::string device_address);
+  device::BluetoothDevice* GetDevice(const std::string& device_address);
 
   // The remote BLE device being searched. It maybe empty, in this case the
   // remote device should advertise |remote_service_uuid_| and

components/search_engines/default_search_manager_unittest.cc

@@ -118,7 +118,8 @@ void SetPolicy(user_prefs::TestingPrefServiceSyncable* prefs,
   prefs->SetManagedPref(kDefaultSearchProviderData, entry.release());
 }
 
-scoped_ptr<TemplateURLData> GenerateDummyTemplateURLData(std::string type) {
+scoped_ptr<TemplateURLData> GenerateDummyTemplateURLData(
+    const std::string& type) {
   scoped_ptr<TemplateURLData> data(new TemplateURLData());
   data->SetShortName(base::UTF8ToUTF16(std::string(type).append("name")));
   data->SetKeyword(base::UTF8ToUTF16(std::string(type).append("key")));

components/search_engines/template_url_parser_unittest.cc

@@ -20,7 +20,7 @@ using base::ASCIIToUTF16;
 // occurrence of value_str_ in its value.
 class ParamFilterImpl : public TemplateURLParser::ParameterFilter {
  public:
-  ParamFilterImpl(std::string name_str, std::string value_str);
+  ParamFilterImpl(const std::string& name_str, const std::string& value_str);
   ~ParamFilterImpl() override;
 
   bool KeepParameter(const std::string& key, const std::string& value) override;
@@ -32,10 +32,9 @@ class ParamFilterImpl : public TemplateURLParser::ParameterFilter {
   DISALLOW_COPY_AND_ASSIGN(ParamFilterImpl);
 };
 
-ParamFilterImpl::ParamFilterImpl(std::string name_str, std::string value_str)
-   : name_str_(name_str),
-     value_str_(value_str) {
-}
+ParamFilterImpl::ParamFilterImpl(const std::string& name_str,
+                                 const std::string& value_str)
+    : name_str_(name_str), value_str_(value_str) {}
 
 ParamFilterImpl::~ParamFilterImpl() {
 }

components/signin/core/browser/about_signin_internals.cc

@@ -343,11 +343,12 @@ void AboutSigninInternals::OnTokenRemoved(
   NotifyObservers();
 }
 
-void AboutSigninInternals::OnRefreshTokenReceived(std::string status) {
+void AboutSigninInternals::OnRefreshTokenReceived(const std::string& status) {
   NotifySigninValueChanged(REFRESH_TOKEN_RECEIVED, status);
 }
 
-void AboutSigninInternals::OnAuthenticationResultReceived(std::string status) {
+void AboutSigninInternals::OnAuthenticationResultReceived(
+    const std::string& status) {
   NotifySigninValueChanged(AUTHENTICATION_RESULT_RECEIVED, status);
 }
 

components/signin/core/browser/about_signin_internals.h

@@ -73,8 +73,8 @@ class AboutSigninInternals
 
   void Initialize(SigninClient* client);
 
-  void OnRefreshTokenReceived(std::string status);
-  void OnAuthenticationResultReceived(std::string status);
+  void OnRefreshTokenReceived(const std::string& status);
+  void OnAuthenticationResultReceived(const std::string& status);
 
   // KeyedService implementation.
   void Shutdown() override;

components/signin/core/browser/account_fetcher_service.cc

@@ -105,7 +105,7 @@ void AccountFetcherService::EnableNetworkFetches() {
   // If there are accounts in |pending_user_info_fetches_|, they were deemed
   // invalid after being loaded from prefs and need to be fetched now instead of
   // waiting after the timer.
-  for (std::string account_id : pending_user_info_fetches_)
+  for (const std::string& account_id : pending_user_info_fetches_)
     StartFetchingUserInfo(account_id);
   pending_user_info_fetches_.clear();
 

components/signin/core/browser/account_tracker_service_unittest.cc

@@ -48,31 +48,31 @@ enum TrackingEventType {
   REMOVED,
 };
 
-std::string AccountIdToEmail(const std::string account_id) {
+std::string AccountIdToEmail(const std::string& account_id) {
   return account_id + "@gmail.com";
 }
 
-std::string AccountIdToGaiaId(const std::string account_id) {
+std::string AccountIdToGaiaId(const std::string& account_id) {
   return "gaia-" + account_id;
 }
 
-std::string AccountIdToFullName(const std::string account_id) {
+std::string AccountIdToFullName(const std::string& account_id) {
   return "full-name-" + account_id;
 }
 
-std::string AccountIdToGivenName(const std::string account_id) {
+std::string AccountIdToGivenName(const std::string& account_id) {
   return "given-name-" + account_id;
 }
 
-std::string AccountIdToLocale(const std::string account_id) {
+std::string AccountIdToLocale(const std::string& account_id) {
   return "locale-" + account_id;
 }
 
-std::string AccountIdToPictureURL(const std::string account_id) {
+std::string AccountIdToPictureURL(const std::string& account_id) {
   return "picture_url-" + account_id;
 }
 
-void CheckAccountDetails(const std::string account_id,
+void CheckAccountDetails(const std::string& account_id,
                          const AccountInfo& info) {
   EXPECT_EQ(account_id, info.account_id);
   EXPECT_EQ(AccountIdToGaiaId(account_id), info.gaia);

components/signin/core/common/profile_management_switches.cc

@@ -106,7 +106,7 @@ State GetProcessState() {
   return state;
 }
 
-bool CheckFlag(std::string command_switch, State min_state) {
+bool CheckFlag(const std::string& command_switch, State min_state) {
   // Individiual flag settings take precedence.
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(command_switch))
     return true;

components/sync_driver/device_info.cc

@@ -106,7 +106,7 @@ base::DictionaryValue* DeviceInfo::ToValue() {
   return value;
 }
 
-void DeviceInfo::set_public_id(std::string id) {
+void DeviceInfo::set_public_id(const std::string& id) {
   public_id_ = id;
 }
 

components/sync_driver/device_info.h

@@ -68,7 +68,7 @@ class DeviceInfo {
   // not unique enough so the user can be tracked. Exposing |guid|
   // would lead to a stable unique id for a device which can potentially
   // be used for tracking.
-  void set_public_id(std::string id);
+  void set_public_id(const std::string& id);
 
   // Converts the |DeviceInfo| values to a JS friendly DictionaryValue,
   // which extension APIs can expose to third party apps.

components/sync_driver/tab_node_pool.cc

@@ -28,8 +28,8 @@ const int TabNodePool::kInvalidTabNodeID = -1;
 TabNodePool::~TabNodePool() {}
 
 // Static
-std::string TabNodePool::TabIdToTag(
-    const std::string machine_tag, int tab_node_id) {
+std::string TabNodePool::TabIdToTag(const std::string& machine_tag,
+                                    int tab_node_id) {
   return base::StringPrintf("%s %d", machine_tag.c_str(), tab_node_id);
 }
 

components/sync_driver/tab_node_pool.h

@@ -55,7 +55,7 @@ class TabNodePool {
   static const int kInvalidTabNodeID;
 
   // Build a sync tag from tab_node_id.
-  static std::string TabIdToTag(const std::string machine_tag,
+  static std::string TabIdToTag(const std::string& machine_tag,
                                 int tab_node_id);
 
   // Returns the tab_node_id for the next free tab node. If none are available,

components/test_runner/test_runner.cc

@@ -216,7 +216,7 @@ class TestRunnerBindings : public gin::Wrappable<TestRunnerBindings> {
   void SetXSSAuditorEnabled(bool enabled);
   void SetAllowUniversalAccessFromFileURLs(bool allow);
   void SetAllowFileAccessFromFileURLs(bool allow);
-  void OverridePreference(const std::string key, v8::Local<v8::Value> value);
+  void OverridePreference(const std::string& key, v8::Local<v8::Value> value);
   void SetAcceptLanguages(const std::string& accept_languages);
   void SetPluginsEnabled(bool enabled);
   void DumpEditingCallbacks();
@@ -292,7 +292,7 @@ class TestRunnerBindings : public gin::Wrappable<TestRunnerBindings> {
   void CopyImageAtAndCapturePixelsAsyncThen(int x,
                                             int y,
                                             v8::Local<v8::Function> callback);
-  void SetCustomTextOutput(std::string output);
+  void SetCustomTextOutput(const std::string& output);
   void SetViewSourceForFrame(const std::string& name, bool enabled);
   void SetBluetoothMockDataSet(const std::string& dataset_name);
   void SetBluetoothManualChooser();
@@ -1054,7 +1054,7 @@ void TestRunnerBindings::SetAllowFileAccessFromFileURLs(bool allow) {
     runner_->SetAllowFileAccessFromFileURLs(allow);
 }
 
-void TestRunnerBindings::OverridePreference(const std::string key,
+void TestRunnerBindings::OverridePreference(const std::string& key,
                                             v8::Local<v8::Value> value) {
   if (runner_)
     runner_->OverridePreference(key, value);
@@ -1450,7 +1450,7 @@ void TestRunnerBindings::CopyImageAtAndCapturePixelsAsyncThen(
     runner_->CopyImageAtAndCapturePixelsAsyncThen(x, y, callback);
 }
 
-void TestRunnerBindings::SetCustomTextOutput(std::string output) {
+void TestRunnerBindings::SetCustomTextOutput(const std::string& output) {
   runner_->setCustomTextOutput(output);
 }
 
@@ -1784,7 +1784,7 @@ std::string TestRunner::customDumpText() const {
   return custom_text_output_;
 }
 
-void TestRunner::setCustomTextOutput(std::string text) {
+void TestRunner::setCustomTextOutput(const std::string& text) {
   custom_text_output_ = text;
   has_custom_text_output_ = true;
 }
@@ -2554,7 +2554,7 @@ void TestRunner::SetAllowFileAccessFromFileURLs(bool allow) {
   delegate_->ApplyPreferences();
 }
 
-void TestRunner::OverridePreference(const std::string key,
+void TestRunner::OverridePreference(const std::string& key,
                                     v8::Local<v8::Value> value) {
   TestPreferences* prefs = delegate_->Preferences();
   if (key == "WebKitDefaultFontSize") {

components/test_runner/test_runner.h

@@ -87,7 +87,7 @@ class TestRunner : public WebTestRunner,
   void ClearDevToolsLocalStorage();
   void setShouldDumpAsText(bool);
   void setShouldDumpAsMarkup(bool);
-  void setCustomTextOutput(std::string text);
+  void setCustomTextOutput(const std::string& text);
   void setShouldGeneratePixelResults(bool);
   void setShouldDumpFrameLoadCallbacks(bool);
   void setShouldDumpPingLoaderCallbacks(bool);
@@ -329,7 +329,7 @@ class TestRunner : public WebTestRunner,
   void SetXSSAuditorEnabled(bool enabled);
   void SetAllowUniversalAccessFromFileURLs(bool allow);
   void SetAllowFileAccessFromFileURLs(bool allow);
-  void OverridePreference(const std::string key, v8::Local<v8::Value> value);
+  void OverridePreference(const std::string& key, v8::Local<v8::Value> value);
 
   // Modify accept_languages in RendererPreferences.
   void SetAcceptLanguages(const std::string& accept_languages);

components/tracing/trace_config_file.cc

@@ -87,7 +87,7 @@ TraceConfigFile::TraceConfigFile()
 TraceConfigFile::~TraceConfigFile() {
 }
 
-bool TraceConfigFile::ParseTraceConfigFileContent(std::string content) {
+bool TraceConfigFile::ParseTraceConfigFileContent(const std::string& content) {
   scoped_ptr<base::Value> value(base::JSONReader::Read(content));
   if (!value || !value->IsType(base::Value::TYPE_DICTIONARY))
     return false;

components/tracing/trace_config_file.h

@@ -81,7 +81,7 @@ class TRACING_EXPORT TraceConfigFile {
   TraceConfigFile();
   ~TraceConfigFile();
 
-  bool ParseTraceConfigFileContent(std::string content);
+  bool ParseTraceConfigFileContent(const std::string& content);
 
   bool is_enabled_;
   base::trace_event::TraceConfig trace_config_;