Inform GetEntropySource of whether or not metrics reporting will be enabled.

chrome/browser/chrome_browser_main.cc

 // Copyright (c) 2012 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 "chrome/browser/chrome_browser_main.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 522 matching lines @@
 #if defined(OS_WIN)
   if (parsed_command_line_.HasSwitch(switches::kChromeFrame))
     MetricsLog::set_version_extension("-F");
 #elif defined(ARCH_CPU_64_BITS)
   MetricsLog::set_version_extension("-64");
 #endif  // defined(OS_WIN)
 
   // Initialize FieldTrialList to support FieldTrials that use one-time
   // randomization.
   MetricsService* metrics = browser_process_->metrics_service();
-  if (IsMetricsReportingEnabled())
+  bool metrics_reporting_enabled = IsMetricsReportingEnabled();
+  if (metrics_reporting_enabled)
     metrics->ForceClientIdCreation();  // Needed below.
   field_trial_list_.reset(
-      new base::FieldTrialList(metrics->GetEntropySource()));
+      new base::FieldTrialList(
+          metrics->GetEntropySource(metrics_reporting_enabled)));
 
   // Ensure any field trials specified on the command line are initialized.
   // Also stop the metrics service so that we don't pollute UMA.
 #ifndef NDEBUG
   const CommandLine* command_line = CommandLine::ForCurrentProcess();
   if (command_line->HasSwitch(switches::kForceFieldTrials)) {
     std::string persistent = command_line->GetSwitchValueASCII(
         switches::kForceFieldTrials);
     bool ret = base::FieldTrialList::CreateTrialsFromString(persistent);
     CHECK(ret) << "Invalid --" << switches::kForceFieldTrials <<
@@ skipping 29 matching lines @@
     return;
   }
 
   if (IsMetricsReportingEnabled())
     metrics->Start();
 }
 
 bool ChromeBrowserMainParts::IsMetricsReportingEnabled() {
   // If the user permits metrics reporting with the checkbox in the
   // prefs, we turn on recording.  We disable metrics completely for
-  // non-official builds.
+  // non-official builds.  This can be forced with a flag.
+  const CommandLine* command_line = CommandLine::ForCurrentProcess();
+  if (command_line->HasSwitch(switches::kEnableMetricsReporting))
+    return true;
+
   bool enabled = false;
 #ifndef NDEBUG
   // The debug build doesn't send UMA logs when FieldTrials are forced.
-  const CommandLine* command_line = CommandLine::ForCurrentProcess();
   if (command_line->HasSwitch(switches::kForceFieldTrials))
     return false;
 #endif  // #ifndef NDEBUG
 
 #if defined(GOOGLE_CHROME_BUILD)
 #if defined(OS_CHROMEOS)
   chromeos::CrosSettings::Get()->GetBoolean(chromeos::kStatsReportingPref,
                                             &enabled);
 #else
   enabled = local_state_->GetBoolean(prefs::kMetricsReportingEnabled);
@@ skipping 913 matching lines @@
     if (base::win::GetVersion() <= base::win::VERSION_XP)
       uma_name += "_XP";
 
     uma_name += "_PreRead_";
     uma_name += pre_read_percentage;
     AddPreReadHistogramTime(uma_name.c_str(), time);
   }
 #endif
 #endif
 }