Fix race with google variation ID registration

chrome/browser/android/data_usage/external_data_use_observer_bridge.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/android/data_usage/external_data_use_observer_bridge.h"
 
 #include <memory>
 #include <vector>
 
 #include "base/android/jni_string.h"
@@ skipping 42 matching lines @@
 }
 
 }  // namespace
 
 namespace chrome {
 
 namespace android {
 
 ExternalDataUseObserverBridge::ExternalDataUseObserverBridge()
     : construct_time_(base::TimeTicks::Now()),
-      is_first_matching_rule_fetch_(true),
-      register_google_variation_id_(false) {
+      is_first_matching_rule_fetch_(true) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
 
   // Detach from IO thread since rest of ExternalDataUseObserverBridge lives on
   // the UI thread.
   thread_checker_.DetachFromThread();
 }
 
 ExternalDataUseObserverBridge::~ExternalDataUseObserverBridge() {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (j_external_data_use_observer_.is_null())
@@ skipping 126 matching lines @@
 
 void ExternalDataUseObserverBridge::ShouldRegisterAsDataUseObserver(
     bool should_register) const {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(!j_external_data_use_observer_.is_null());
 
   io_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&ExternalDataUseObserver::ShouldRegisterAsDataUseObserver,
                  external_data_use_observer_, should_register));
+}
 
-  if (!register_google_variation_id_)
-    return;
-
+void ExternalDataUseObserverBridge::RegisterGoogleVariationID(
+    bool should_register) {
+  DCHECK(thread_checker_.CalledOnValidThread());
   variations::VariationID variation_id = GetGoogleVariationID();
 
   if (variation_id != variations::EMPTY_ID) {
     // Set variation id for the enabled group if |should_register| is true.
     // Otherwise clear the variation id for the enabled group by setting to
     // EMPTY_ID.
-    variations::AssociateGoogleVariationID(
-        variations::GOOGLE_WEB_PROPERTIES, kSyntheticFieldTrial,
-        kSyntheticFieldTrialEnabledGroup,
-        should_register ? variation_id : variations::EMPTY_ID);
+    if (should_register) {
+      variations::AssociateGoogleVariationID(
+          variations::GOOGLE_WEB_PROPERTIES, kSyntheticFieldTrial,
+          kSyntheticFieldTrialEnabledGroup, variation_id);
+    }
     ChromeMetricsServiceAccessor::RegisterSyntheticFieldTrial(
         kSyntheticFieldTrial, should_register
                                   ? kSyntheticFieldTrialEnabledGroup
                                   : kSyntheticFieldTrialDisabledGroup);
   }
 }
 
-void ExternalDataUseObserverBridge::SetRegisterGoogleVariationID(
-    bool register_google_variation_id) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  register_google_variation_id_ = register_google_variation_id;
-}
-
 bool RegisterExternalDataUseObserver(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace android
 
 }  // namespace chrome