Clarify that NTPSnippetsBridge holds a Java SnippetsBridge.

chrome/browser/android/ntp/ntp_snippets_bridge.cc

 // Copyright 2016 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/ntp/ntp_snippets_bridge.h"
 
 #include <jni.h>
 #include <utility>
 #include <vector>
 
@@ skipping 92 matching lines @@
   // Can maybe be null in some cases? (Incognito profile?) crbug.com/647920
   if (!content_suggestions_service) {
     return nullptr;
   }
   return content_suggestions_service->remote_suggestions_scheduler();
 }
 
 }  // namespace
 
 static jlong Init(JNIEnv* env,
-                  const JavaParamRef<jobject>& obj,
+                  const JavaParamRef<jobject>& j_bridge,
                   const JavaParamRef<jobject>& j_profile) {
-  NTPSnippetsBridge* snippets_bridge = new NTPSnippetsBridge(env, j_profile);
+  NTPSnippetsBridge* snippets_bridge =
+      new NTPSnippetsBridge(env, j_bridge, j_profile);
   return reinterpret_cast<intptr_t>(snippets_bridge);
 }
 
 // Initiates a background fetch for remote suggestions.
 static void RemoteSuggestionsSchedulerOnFetchDue(
     JNIEnv* env,
     const JavaParamRef<jclass>& caller) {
   ntp_snippets::RemoteSuggestionsScheduler* scheduler =
       GetRemoteSuggestionsScheduler();
   if (!scheduler) {
@@ skipping 22 matching lines @@
 static void OnSuggestionTargetVisited(JNIEnv* env,
                                       const JavaParamRef<jclass>& caller,
                                       jint j_category_id,
                                       jlong visit_time_ms) {
   ntp_snippets::metrics::OnSuggestionTargetVisited(
       Category::FromIDValue(j_category_id),
       base::TimeDelta::FromMilliseconds(visit_time_ms));
 }
 
 NTPSnippetsBridge::NTPSnippetsBridge(JNIEnv* env,
+                                     const JavaParamRef<jobject>& j_bridge,
                                      const JavaParamRef<jobject>& j_profile)
-    : content_suggestions_service_observer_(this), weak_ptr_factory_(this) {
+    : content_suggestions_service_observer_(this),
+      bridge_(env, j_bridge),
+      weak_ptr_factory_(this) {
   Profile* profile = ProfileAndroid::FromProfileAndroid(j_profile);
   content_suggestions_service_ =
       ContentSuggestionsServiceFactory::GetForProfile(profile);
   history_service_ =
       HistoryServiceFactory::GetForProfile(profile,
                                            ServiceAccessType::EXPLICIT_ACCESS);
   content_suggestions_service_observer_.Add(content_suggestions_service_);
 }
 
 void NTPSnippetsBridge::Destroy(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   delete this;
 }
 
-void NTPSnippetsBridge::SetObserver(JNIEnv* env,
-                                    const JavaParamRef<jobject>& obj,
-                                    const JavaParamRef<jobject>& j_observer) {
-  observer_.Reset(env, j_observer);
-}
-
 ScopedJavaLocalRef<jintArray> NTPSnippetsBridge::GetCategories(
     JNIEnv* env,
     const base::android::JavaParamRef<jobject>& obj) {
   std::vector<int> category_ids;
   for (Category category : content_suggestions_service_->GetCategories()) {
     category_ids.push_back(category.id());
   }
   return ToJavaIntArray(env, category_ids);
 }
 
@@ skipping 209 matching lines @@
 
 void NTPSnippetsBridge::OnNTPInitialized(
     JNIEnv* env,
     const base::android::JavaParamRef<jobject>& obj) {
   content_suggestions_service_->remote_suggestions_scheduler()->OnNTPOpened();
 }
 
 NTPSnippetsBridge::~NTPSnippetsBridge() {}
 
 void NTPSnippetsBridge::OnNewSuggestions(Category category) {
-  if (observer_.is_null()) {
+  if (bridge_.is_null()) {

[Bernhard Bauer, 2017/01/04 17:27:34]

Hm, we now know that |bridge_| is non-null, right? 

[Michael van Ouwerkerk, 2017/01/05 11:35:40]

I think it could be, as it is reset in ContentSuggestionsServiceShutdown.

[Bernhard Bauer, 2017/01/05 11:57:47]

But in that case we shouldn't get called back anymore, right?

(Also, does that even happen on Android? 😃)

[Michael van Ouwerkerk, 2017/01/05 12:15:55]

Done.

     return;
   }
 
   JNIEnv* env = base::android::AttachCurrentThread();
-  Java_SnippetsBridge_onNewSuggestions(env, observer_,
+  Java_SnippetsBridge_onNewSuggestions(env, bridge_,
                                        static_cast<int>(category.id()));
 }
 
 void NTPSnippetsBridge::OnCategoryStatusChanged(Category category,
                                                 CategoryStatus new_status) {
-  if (observer_.is_null()) {
+  if (bridge_.is_null()) {
     return;
   }
 
   JNIEnv* env = base::android::AttachCurrentThread();
-  Java_SnippetsBridge_onCategoryStatusChanged(env, observer_,
+  Java_SnippetsBridge_onCategoryStatusChanged(env, bridge_,
                                               static_cast<int>(category.id()),
                                               static_cast<int>(new_status));
 }
 
 void NTPSnippetsBridge::OnSuggestionInvalidated(
     const ContentSuggestion::ID& suggestion_id) {
-  if (observer_.is_null()) {
+  if (bridge_.is_null()) {
     return;
   }
 
   JNIEnv* env = base::android::AttachCurrentThread();
   Java_SnippetsBridge_onSuggestionInvalidated(
-      env, observer_.obj(), static_cast<int>(suggestion_id.category().id()),
+      env, bridge_.obj(), static_cast<int>(suggestion_id.category().id()),
       ConvertUTF8ToJavaString(env, suggestion_id.id_within_category()).obj());
 }
 
 void NTPSnippetsBridge::OnFullRefreshRequired() {
-  if (observer_.is_null()) {
+  if (bridge_.is_null()) {
     return;
   }
 
   JNIEnv* env = base::android::AttachCurrentThread();
-  Java_SnippetsBridge_onFullRefreshRequired(env, observer_.obj());
+  Java_SnippetsBridge_onFullRefreshRequired(env, bridge_.obj());
 }
 
 void NTPSnippetsBridge::ContentSuggestionsServiceShutdown() {
-  observer_.Reset();
+  bridge_.Reset();
   content_suggestions_service_observer_.Remove(content_suggestions_service_);
 }
 
 void NTPSnippetsBridge::OnImageFetched(ScopedJavaGlobalRef<jobject> callback,
                                        const gfx::Image& image) {
   ScopedJavaLocalRef<jobject> j_bitmap;
   if (!image.IsEmpty()) {
     j_bitmap = gfx::ConvertToJavaBitmap(image.ToSkBitmap());
   }
   base::android::RunCallbackAndroid(callback, j_bitmap);
 }
 
 void NTPSnippetsBridge::OnSuggestionsFetched(
     Category category,
     ntp_snippets::Status status,
     std::vector<ContentSuggestion> suggestions) {
   // TODO(fhorschig, dgn): Allow refetch or show notification acc. to status.
   JNIEnv* env = AttachCurrentThread();
   Java_SnippetsBridge_onMoreSuggestions(
-      env, observer_, category.id(),
+      env, bridge_, category.id(),
       ToJavaSuggestionList(env, category, suggestions));
 }
 
 // static
 bool NTPSnippetsBridge::Register(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }