Add an override flag to enable metrics reporting.

chrome/common/chrome_switches.h

Index: chrome/common/chrome_switches.h
diff --git a/chrome/common/chrome_switches.h b/chrome/common/chrome_switches.h
index a8b2b351affdf6acab5cea10591a1f5491db1f2c..630650d600bb8cdbb2250f10141e4cae976fd7ec 100644
--- a/chrome/common/chrome_switches.h
+++ b/chrome/common/chrome_switches.h
@@ -112,16 +112,17 @@ extern const char kEnableDeviceDiscoveryNotifications[];
 extern const char kEnableDevToolsExperiments[];
 extern const char kEnableDomainReliability[];
 extern const char kEnableExperimentalHotwordHardware[];
-extern const char kEnableExtensionActivityLogging[];
 extern const char kEnableExtensionActivityLogTesting[];
+extern const char kEnableExtensionActivityLogging[];
 extern const char kEnableFastUnload[];
 extern const char kEnableMaterialDesignFeedback[];
 extern const char kEnableMaterialDesignPolicyPage[];
+extern const char kEnableMetricsReportingForTesting[];
 extern const char kEnableNaCl[];
 extern const char kEnableNavigationTracing[];
 extern const char kEnableNetBenchmarking[];
-extern const char kEnableOfflineAutoReload[];
 extern const char kEnableOfflineAutoReloadVisibleOnly[];
+extern const char kEnableOfflineAutoReload[];
 extern const char kEnablePermissionActionReporting[];
 extern const char kEnablePotentiallyAnnoyingSecurityFeatures[];
 extern const char kEnablePowerOverlay[];
@@ -139,9 +140,9 @@ extern const char kEnableThumbnailRetargeting[];
 extern const char kEnableUserAlternateProtocolPorts[];
 extern const char kEnableWebNotificationCustomLayouts[];
 extern const char kEnableWebRtcEventLoggingFromExtension[];
-extern const char kExtensionContentVerification[];
 extern const char kExtensionContentVerificationBootstrap[];
 extern const char kExtensionContentVerificationEnforce[];
+extern const char kExtensionContentVerification[];
 extern const char kExtensionContentVerificationEnforceStrict[];
 extern const char kExtensionsInstallVerification[];
 extern const char kExtensionsNotWebstore[];