Snippets are enabled when search suggestions are enabled.

chrome/browser/ntp_snippets/ntp_snippets_service_factory.cc

Index: chrome/browser/ntp_snippets/ntp_snippets_service_factory.cc
diff --git a/chrome/browser/ntp_snippets/ntp_snippets_service_factory.cc b/chrome/browser/ntp_snippets/ntp_snippets_service_factory.cc
index 17dbfc27177760cb259731f356b7922c19a899d0..6ae606b8b7ee3d8182220ea5a61fc9561755a554 100644
--- a/chrome/browser/ntp_snippets/ntp_snippets_service_factory.cc
+++ b/chrome/browser/ntp_snippets/ntp_snippets_service_factory.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/ntp_snippets/ntp_snippets_service_factory.h"
 
+#include "base/feature_list.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/singleton.h"
 #include "chrome/browser/browser_process.h"
@@ -14,12 +15,14 @@
 #include "chrome/browser/signin/signin_manager_factory.h"
 #include "chrome/browser/sync/profile_sync_service_factory.h"
 #include "chrome/common/channel_info.h"
+#include "chrome/common/pref_names.h"
 #include "components/browser_sync/browser/profile_sync_service.h"
 #include "components/image_fetcher/image_fetcher.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 #include "components/ntp_snippets/ntp_snippets_fetcher.h"
 #include "components/ntp_snippets/ntp_snippets_scheduler.h"
 #include "components/ntp_snippets/ntp_snippets_service.h"
+#include "components/prefs/pref_service.h"
 #include "components/safe_json/safe_json_parser.h"
 #include "components/signin/core/browser/profile_oauth2_token_service.h"
 #include "components/signin/core/browser/signin_manager.h"
@@ -30,6 +33,7 @@
 #include "net/url_request/url_request_context_getter.h"
 
 #if defined(OS_ANDROID)
+#include "chrome/browser/android/chrome_feature_list.h"
 #include "chrome/browser/android/ntp/ntp_snippets_launcher.h"
 #endif  // OS_ANDROID
 
@@ -66,6 +70,15 @@ NTPSnippetsServiceFactory::~NTPSnippetsServiceFactory() {}
 KeyedService* NTPSnippetsServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   Profile* profile = Profile::FromBrowserContext(context);
+
+  // TODO(mvanouwerkerk): Move the enable logic into the service once we start
+  // observing pref changes.
+  bool enabled = profile->GetPrefs()->GetBoolean(prefs::kSearchSuggestEnabled);

[dgn, 2016/05/24 16:38:35]

Why not starting to listen to pref changes now? It seems like a better solution
that only applying the changes to newly opened tabs.

[Marc Treib, 2016/05/24 16:55:24]

Actually, this current code only applies at Chrome startup.
Listening to pref changes will absolutely need to happen, but I'm okay with
doing it in a follow-up CL if that makes things easier.

[Michael van Ouwerkerk, 2016/05/24 16:58:09]

Because such a change is more involved, and I'd like to land these changes
separately now as they solve the majority of the use case. The codebase is
changing quickly, and I'd like to avoid additional merge conflicts, like from
your current series of CLs :-)

+#if defined(OS_ANDROID)
+  enabled = enabled &&
+            base::FeatureList::IsEnabled(chrome::android::kNTPSnippetsFeature);
+#endif  // OS_ANDROID
+
   SigninManagerBase* signin_manager =
       SigninManagerFactory::GetForProfile(profile);
   OAuth2TokenService* token_service =
@@ -90,8 +103,8 @@ KeyedService* NTPSnippetsServiceFactory::BuildServiceInstanceFor(
               base::SequencedWorkerPool::CONTINUE_ON_SHUTDOWN);
 
   return new ntp_snippets::NTPSnippetsService(
-      profile->GetPrefs(), sync_service, suggestions_service, task_runner,
-      g_browser_process->GetApplicationLocale(), scheduler,
+      enabled, profile->GetPrefs(), sync_service, suggestions_service,
+      task_runner, g_browser_process->GetApplicationLocale(), scheduler,
       base::WrapUnique(new ntp_snippets::NTPSnippetsFetcher(
           signin_manager, token_service, request_context,
           base::Bind(&safe_json::SafeJsonParser::Parse),