Restrict sending GWS ID only to signed in users

chrome/browser/android/data_usage/external_data_use_observer_bridge.cc

Index: chrome/browser/android/data_usage/external_data_use_observer_bridge.cc
diff --git a/chrome/browser/android/data_usage/external_data_use_observer_bridge.cc b/chrome/browser/android/data_usage/external_data_use_observer_bridge.cc
index 01f57f4fc9366e3da0a15c7a53a07ad7c32434c3..51cec14eb42ea26d05a09824a26a1d52f5070680 100644
--- a/chrome/browser/android/data_usage/external_data_use_observer_bridge.cc
+++ b/chrome/browser/android/data_usage/external_data_use_observer_bridge.cc
@@ -17,6 +17,10 @@
 #include "chrome/browser/android/data_usage/data_use_tab_model.h"
 #include "chrome/browser/android/data_usage/external_data_use_observer.h"
 #include "chrome/browser/metrics/chrome_metrics_service_accessor.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/signin/signin_manager_factory.h"
+#include "components/signin/core/browser/signin_manager.h"
 #include "components/variations/variations_associated_data.h"
 #include "content/public/browser/browser_thread.h"
 #include "jni/ExternalDataUseObserver_jni.h"
@@ -211,7 +215,17 @@ void ExternalDataUseObserverBridge::ShouldRegisterAsDataUseObserver(
                  external_data_use_observer_, should_register));
 
   variations::VariationID variation_id = GetGoogleVariationID();
-  if (variation_id != variations::EMPTY_ID) {
+  Profile* profile = ProfileManager::GetLastUsedProfile();
+  DCHECK(profile);

[tbansal1, 2016/12/12 18:55:23]

nit: DCHECK is not required since if the |profile| is null, Chromium will
anyways crash on the next line where profile is dereferenced.

+
+  // Skip registering synthetic field trial for incognito profiles.
+  if (profile->GetProfileType() == INCOGNITO_PROFILE)
+    return;
+
+  const SigninManager* signin_manager =
+      SigninManagerFactory::GetForProfileIfExists(profile);
+  if (variation_id != variations::EMPTY_ID && signin_manager &&
+      signin_manager->IsAuthenticated()) {
     // 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.