Add an override flag to enable metrics reporting.

This simplifies local testing of metrics collection, particularly in dev builds.

BUG=717792

Review-Url: https://codereview.chromium.org/2861563002
Cr-Commit-Position: refs/heads/master@{#469526}

chrome/browser/metrics/chrome_metrics_service_client.cc

@@ -570,6 +570,12 @@ ChromeMetricsServiceClient::GetMetricsReportingDefaultState() {
       g_browser_process->local_state());
 }
 
+// static
+bool ChromeMetricsServiceClient::IsMetricsReportingForceEnabled() {
+  return base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kForceEnableMetricsReporting);
+}
+
 void ChromeMetricsServiceClient::Initialize() {
   PrefService* local_state = g_browser_process->local_state();
 
@@ -585,7 +591,8 @@ void ChromeMetricsServiceClient::Initialize() {
 
   RegisterMetricsServiceProviders();
 
-  if (base::FeatureList::IsEnabled(ukm::kUkmFeature)) {
+  if (IsMetricsReportingForceEnabled() ||
+      base::FeatureList::IsEnabled(ukm::kUkmFeature)) {
     ukm_service_.reset(new ukm::UkmService(local_state, this));
     RegisterUKMProviders();
   }

chrome/browser/metrics/chrome_metrics_service_client.h

@@ -64,6 +64,9 @@ class ChromeMetricsServiceClient : public metrics::MetricsServiceClient,
   // Registers local state prefs used by this class.
   static void RegisterPrefs(PrefRegistrySimple* registry);
 
+  // Checks if the user has forced metrics collection on via the override flag.
+  static bool IsMetricsReportingForceEnabled();
+
   // metrics::MetricsServiceClient:
   metrics::MetricsService* GetMetricsService() override;
   ukm::UkmService* GetUkmService() override;

chrome/browser/metrics/chrome_metrics_services_manager_client.cc

@@ -288,3 +288,7 @@ ChromeMetricsServicesManagerClient::GetMetricsStateManager() {
   }
   return metrics_state_manager_.get();
 }
+
+bool ChromeMetricsServicesManagerClient::IsMetricsReportingForceEnabled() {
+  return ChromeMetricsServiceClient::IsMetricsReportingForceEnabled();
+}

chrome/browser/metrics/chrome_metrics_services_manager_client.h

@@ -79,6 +79,8 @@ class ChromeMetricsServicesManagerClient
   void UpdateRunningServices(bool may_record, bool may_upload) override;
 #endif  // defined(OS_WIN)
 
+  bool IsMetricsReportingForceEnabled() override;
+
   // Gets the MetricsStateManager, creating it if it has not already been
   // created.
   metrics::MetricsStateManager* GetMetricsStateManager();

chrome/common/chrome_switches.cc

@@ -484,6 +484,9 @@ const char kForceDesktopIOSPromotion[] = "force-desktop-ios-promotion";
 // connection type.
 const char kForceEffectiveConnectionType[] = "force-effective-connection-type";
 
+// Forces metrics reporting to be enabled.
+const char kForceEnableMetricsReporting[] = "force-enable-metrics-reporting";
+
 // Displays the First Run experience when the browser is started, regardless of
 // whether or not it's actually the First Run (this overrides kNoFirstRun).
 const char kForceFirstRun[]                 = "force-first-run";

chrome/common/chrome_switches.h

@@ -150,6 +150,7 @@ extern const char kForceAndroidAppMode[];
 extern const char kForceAppMode[];
 extern const char kForceDesktopIOSPromotion[];
 extern const char kForceEffectiveConnectionType[];
+extern const char kForceEnableMetricsReporting[];
 extern const char kForceFirstRun[];
 extern const char kForceLocalNtp[];
 extern const char kForceVariationIds[];

components/metrics_services_manager/BUILD.gn

@@ -6,6 +6,7 @@ static_library("metrics_services_manager") {
   sources = [
     "metrics_services_manager.cc",
     "metrics_services_manager.h",
+    "metrics_services_manager_client.cc",
     "metrics_services_manager_client.h",
   ]
 

components/metrics_services_manager/metrics_services_manager.cc

@@ -132,6 +132,7 @@ void MetricsServicesManager::UpdateUkmService() {
   if (!ukm)
     return;
   bool sync_enabled =
+      client_->IsMetricsReportingForceEnabled() ||
       metrics_service_client_->IsHistorySyncEnabledOnAllProfiles();
   if (may_record_ && sync_enabled) {
     ukm->EnableRecording();
@@ -146,7 +147,9 @@ void MetricsServicesManager::UpdateUkmService() {
 }
 
 void MetricsServicesManager::UpdateUploadPermissions(bool may_upload) {
-  UpdatePermissions(client_->IsMetricsReportingEnabled(), may_upload);
+  UpdatePermissions((client_->IsMetricsReportingForceEnabled() ||
+                     client_->IsMetricsReportingEnabled()),
+                    client_->IsMetricsReportingForceEnabled() || may_upload);
 }
 
 }  // namespace metrics_services_manager

components/metrics_services_manager/metrics_services_manager_client.cc

+// Copyright 2014 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 "components/metrics_services_manager/metrics_services_manager_client.h"
+
+namespace metrics_services_manager {
+
+bool MetricsServicesManagerClient::IsMetricsReportingForceEnabled() {
+  return false;
+}
+
+}  // namespace metrics_services_manager

components/metrics_services_manager/metrics_services_manager_client.h

@@ -57,6 +57,9 @@ class MetricsServicesManagerClient {
   // Update the running state of metrics services managed by the embedder, for
   // example, crash reporting.
   virtual void UpdateRunningServices(bool may_record, bool may_upload) {}
+
+  // If the user has forced metrics collection on via the override flag.
+  virtual bool IsMetricsReportingForceEnabled();
 };
 
 }  // namespace metrics_services_manager