Clean Read/SetExperimentLabels to remove check for Chrome build.

chrome/browser/metrics/variations/chrome_variations_service_client.cc

 // Copyright 2015 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/metrics/variations/chrome_variations_service_client.h"
 
 #include "base/bind.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/common/channel_info.h"
 #include "components/version_info/version_info.h"
 #include "content/public/browser/browser_thread.h"
 
 #if defined(OS_WIN)
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string16.h"
 #include "base/threading/thread_restrictions.h"
 #include "chrome/installer/util/google_update_settings.h"
+#include "chrome/installer/util/install_modes.h"

[grt (UTC plus 2), 2017/06/02 13:29:28]

installer/util -> install_static
and move into proper sorted position

[nikunjb, 2017/06/02 21:31:43]

Acknowledged. (No longer needed)

 #include "chrome/installer/util/install_util.h"
 #include "components/variations/experiment_labels.h"
 #endif
 
 #if !defined(OS_ANDROID) && !defined(OS_CHROMEOS)
 #include "chrome/browser/upgrade_detector_impl.h"
 #endif
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/settings/cros_settings.h"
@@ skipping 12 matching lines @@
 #endif  // !defined(OS_ANDROID) && !defined(OS_CHROMEOS)
 
   // TODO(asvitkine): Get the version that will be used on restart instead of
   // the current version on Android, iOS and ChromeOS.
   return base::Version(version_info::GetVersionNumber());
 }
 
 #if defined(OS_WIN)
 // Clear all Variations experiment labels from Google Update Registry Labels.
 // TODO(jwd): Remove this once we're confident most clients no longer have these
 // labels (M57-M58 timeframe).

[Alexei Svitkine (slow), 2017/06/02 15:11:41]

We have a TODO here to remove this code entirely. Instead of making further
changes, can we simply delete this code?

(The context is we used to integrate with Google Update to plumb some
experiments through to it. When we removed this support last year, we left this
code in to clean up existing registry keys. By this point, they've probably all
been cleaned up and we could just delete this code.)

[grt (UTC plus 2), 2017/06/02 15:16:52]

SGTM to delete the code in metrics. We're keeping the code in installer/util for
use in the upcoming retention experiment.

 void ClearGoogleUpdateRegistryLabels() {
   base::ThreadRestrictions::AssertIOAllowed();
-
+  // There is nothing to do if this brand does not support integration with
+  // Google Update.
+  if (!install_static::kUseGoogleUpdateIntegration)
+    return;
   // Note that all registry operations are done here on the UI thread as there
   // are no threading restrictions on them.
   const bool is_system_install = !InstallUtil::IsPerUserInstall();
 
   // Read the current bits from the registry.
   base::string16 registry_labels;
   bool success = GoogleUpdateSettings::ReadExperimentLabels(is_system_install,
                                                             &registry_labels);
 
   if (!success) {
@@ skipping 68 matching lines @@
 #if defined(OS_WIN)
   // TODO(jwd): Remove this once we're confident most clients no longer have
   // these labels (M57-M58 timeframe).
   // Do the work on a blocking pool thread, as chrome://profiler has shown that
   // it can cause jank if done on the UI thrread.
   content::BrowserThread::GetBlockingPool()->PostDelayedTask(
       FROM_HERE, base::Bind(&ClearGoogleUpdateRegistryLabels),
       base::TimeDelta::FromSeconds(5));
 #endif
 }