[NTP Snippets] Refresh the displayed snippets less frequently

chrome/browser/android/ntp/ntp_snippets_bridge.cc

Index: chrome/browser/android/ntp/ntp_snippets_bridge.cc
diff --git a/chrome/browser/android/ntp/ntp_snippets_bridge.cc b/chrome/browser/android/ntp/ntp_snippets_bridge.cc
index b1154ceb7fe7c429fdbc60cd003f62fc899a03ac..89211d0d2b6f0483f8eac7bcf289ba92e9938af4 100644
--- a/chrome/browser/android/ntp/ntp_snippets_bridge.cc
+++ b/chrome/browser/android/ntp/ntp_snippets_bridge.cc
@@ -41,14 +41,14 @@ NTPSnippetsBridge::NTPSnippetsBridge(JNIEnv* env,
     : snippet_service_observer_(this) {
   Profile* profile = ProfileAndroid::FromProfileAndroid(j_profile);
   ntp_snippets_service_ = NTPSnippetsServiceFactory::GetForProfile(profile);
+  snippet_service_observer_.Add(ntp_snippets_service_);
 }
 
 void NTPSnippetsBridge::SetObserver(JNIEnv* env,
                                     const JavaParamRef<jobject>& obj,
                                     const JavaParamRef<jobject>& j_observer) {
   observer_.Reset(env, j_observer);
-  // This will call NTPSnippetsServiceLoaded.
-  snippet_service_observer_.Add(ntp_snippets_service_);
+  NTPSnippetsServiceLoaded();
 }
 
 NTPSnippetsBridge::~NTPSnippetsBridge() {}
@@ -65,7 +65,8 @@ void NTPSnippetsBridge::DiscardSnippet(JNIEnv* env,
 }
 
 void NTPSnippetsBridge::NTPSnippetsServiceLoaded() {
-  DCHECK(!observer_.is_null());
+  if (observer_.is_null())
+    return;
 
   std::vector<std::string> titles;
   std::vector<std::string> urls;