[NTP] SnippetsBridge fetchContextualSuggestions

fetchContextualSuggestions in SnippetsBridge fetches contextual
suggestions.
SnippetsBridge provides a new method fetchContextualSuggestionImage
to retrieve an image for a given contextual suggestion.
With this, the contextual feature is operational behind the
flag "contextual-suggestions-carousel".

Bug: 749988
Change-Id: Iee862d3d103ecc2c3e513e425ac9e0e9bd508093
Reviewed-on: https://chromium-review.googlesource.com/589148
Commit-Queue: Andre Gaschler <gaschler@chromium.org>
Reviewed-by: Nicolas Dossou-Gbété <dgn@chromium.org>
Reviewed-by: Jan Krcal <jkrcal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491293}

chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetArticle.java

@@ -133,6 +133,11 @@ public class SnippetArticle implements OfflinableSuggestion {
         return mCategory == KnownCategories.ARTICLES;
     }
 
+    /** @return whether a snippet is a contextual suggestion. */
+    public boolean isContextual() {
+        return mCategory == KnownCategories.CONTEXTUAL;
+    }
+
     /** @return whether a snippet is either offline page or asset download. */
     public boolean isDownload() {
         return mCategory == KnownCategories.DOWNLOADS;

chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetsBridge.java

@@ -158,6 +158,14 @@ public class SnippetsBridge implements SuggestionsSource {
         nativeFetchContextualSuggestions(mNativeSnippetsBridge, url, callback);
     }
 
+    @Override
+    public void fetchContextualSuggestionImage(
+            SnippetArticle suggestion, Callback<Bitmap> callback) {
+        assert mNativeSnippetsBridge != 0;
+        nativeFetchContextualSuggestionImage(mNativeSnippetsBridge, suggestion.mCategory,
+                suggestion.mIdWithinCategory, callback);
+    }
+
     @Override
     public void dismissSuggestion(SnippetArticle suggestion) {
         assert mNativeSnippetsBridge != 0;
@@ -287,6 +295,8 @@ public class SnippetsBridge implements SuggestionsSource {
             String[] knownSuggestions, Callback<List<SnippetArticle>> callback);
     private native void nativeFetchContextualSuggestions(
             long nativeNTPSnippetsBridge, String url, Callback<List<SnippetArticle>> callback);
+    private native void nativeFetchContextualSuggestionImage(long nativeNTPSnippetsBridge,
+            int category, String idWithinCategory, Callback<Bitmap> callback);
     private native void nativeDismissSuggestion(long nativeNTPSnippetsBridge, String url,
             int globalPosition, int category, int positionInCategory, String idWithinCategory);
     private native void nativeDismissCategory(long nativeNTPSnippetsBridge, int category);

chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SuggestionsSource.java

@@ -112,6 +112,12 @@ public interface SuggestionsSource {
      */
     void fetchContextualSuggestions(String url, Callback<List<SnippetArticle>> callback);
 
+    /**
+     * Fetches the thumbnail image for a contextual suggestion. A {@code null} Bitmap is returned if
+     * no image is available.
+     */
+    void fetchContextualSuggestionImage(SnippetArticle suggestion, Callback<Bitmap> callback);
+
     /**
      * Tells the source to dismiss the content suggestion.
      */

chrome/android/java/src/org/chromium/chrome/browser/suggestions/ImageFetcher.java

@@ -98,8 +98,12 @@ public class ImageFetcher {
     public void makeArticleThumbnailRequest(SnippetArticle suggestion, Callback<Bitmap> callback) {
         assert !mIsDestroyed;
 
+        if (suggestion.isContextual()) {
+            mSuggestionsSource.fetchContextualSuggestionImage(suggestion, callback);
+        } else {
             mSuggestionsSource.fetchSuggestionImage(suggestion, callback);
         }
+    }
 
     /**
      * Creates a request for favicon for the URL of a suggestion.

chrome/browser/android/ntp/ntp_snippets_bridge.cc

@@ -337,24 +337,28 @@ void NTPSnippetsBridge::FetchContextualSuggestions(
     const JavaParamRef<jobject>& j_callback) {
   DCHECK(base::FeatureList::IsEnabled(
       chrome::android::kContextualSuggestionsCarousel));
+  GURL url(ConvertJavaStringToUTF8(env, j_url));
+  content_suggestions_service_->contextual_suggestions_source()
+      ->FetchContextualSuggestions(
+          url, base::Bind(&NTPSnippetsBridge::OnContextualSuggestionsFetched,
+                          weak_ptr_factory_.GetWeakPtr(),
+                          ScopedJavaGlobalRef<jobject>(j_callback)));
+}
 
-  // We don't currently have a contextual suggestions service or provider, so
-  // we use articles as placeholders.
-  Category category = Category::FromKnownCategory(KnownCategories::ARTICLES);
-  auto suggestions = ToJavaSuggestionList(
-      env, category,
-      content_suggestions_service_->GetSuggestionsForCategory(category));
-
-  // We would eventually have to hit the network or a database, so let's
-  // pretend here the call is asynchronous.
-  base::ThreadTaskRunnerHandle::Get()->PostTask(
-      FROM_HERE, base::BindOnce(
-                     [](const base::android::JavaRef<jobject>& j_callback,
-                        const base::android::JavaRef<jobject>& j_suggestions) {
-                       RunCallbackAndroid(j_callback, j_suggestions);
-                     },
-                     ScopedJavaGlobalRef<jobject>(j_callback),
-                     ScopedJavaGlobalRef<jobject>(suggestions)));
+void NTPSnippetsBridge::FetchContextualSuggestionImage(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    jint j_category_id,
+    const JavaParamRef<jstring>& id_within_category,
+    const JavaParamRef<jobject>& j_callback) {
+  ScopedJavaGlobalRef<jobject> callback(j_callback);
+  content_suggestions_service_->contextual_suggestions_source()
+      ->FetchContextualSuggestionImage(
+          ContentSuggestion::ID(
+              Category::FromIDValue(j_category_id),
+              ConvertJavaStringToUTF8(env, id_within_category)),
+          base::Bind(&NTPSnippetsBridge::OnImageFetched,
+                     weak_ptr_factory_.GetWeakPtr(), callback));
 }
 
 void NTPSnippetsBridge::ReloadSuggestions(JNIEnv* env,
@@ -458,3 +462,15 @@ void NTPSnippetsBridge::OnSuggestionsFetched(
   RunCallbackAndroid(callback,
                      ToJavaSuggestionList(env, category, suggestions));
 }
+
+void NTPSnippetsBridge::OnContextualSuggestionsFetched(
+    ScopedJavaGlobalRef<jobject> j_callback,
+    ntp_snippets::Status status,
+    const GURL& url,
+    std::vector<ContentSuggestion> suggestions) {
+  JNIEnv* env = AttachCurrentThread();
+  auto j_suggestions = ToJavaSuggestionList(
+      env, Category::FromKnownCategory(KnownCategories::CONTEXTUAL),
+      suggestions);
+  RunCallbackAndroid(j_callback, j_suggestions);
+}

chrome/browser/android/ntp/ntp_snippets_bridge.h

@@ -84,6 +84,13 @@ class NTPSnippetsBridge
       const base::android::JavaParamRef<jstring>& j_url,
       const base::android::JavaParamRef<jobject>& j_callback);
 
+  void FetchContextualSuggestionImage(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      jint j_category_id,
+      const base::android::JavaParamRef<jstring>& id_within_category,
+      const base::android::JavaParamRef<jobject>& j_callback);
+
   void ReloadSuggestions(JNIEnv* env,
                          const base::android::JavaParamRef<jobject>& obj);
 
@@ -125,6 +132,12 @@ class NTPSnippetsBridge
       ntp_snippets::Status status,
       std::vector<ntp_snippets::ContentSuggestion> suggestions);
 
+  void OnContextualSuggestionsFetched(
+      base::android::ScopedJavaGlobalRef<jobject> j_callback,
+      ntp_snippets::Status status,
+      const GURL& url,
+      std::vector<ntp_snippets::ContentSuggestion> suggestions);
+
   ntp_snippets::ContentSuggestionsService* content_suggestions_service_;
   history::HistoryService* history_service_;
   base::CancelableTaskTracker tracker_;

chrome/test/android/javatests/src/org/chromium/chrome/test/util/browser/suggestions/FakeSuggestionsSource.java

@@ -243,6 +243,12 @@ public class FakeSuggestionsSource implements SuggestionsSource {
         throw new UnsupportedOperationException();
     }
 
+    @Override
+    public void fetchContextualSuggestionImage(
+            SnippetArticle suggestion, Callback<Bitmap> callback) {
+        throw new UnsupportedOperationException();
+    }
+
     @Override
     public void addObserver(Observer observer) {
         mObserverList.addObserver(observer);

components/ntp_snippets/content_suggestions_service.h

@@ -280,6 +280,11 @@ class ContentSuggestionsService : public KeyedService,
 
   CategoryRanker* category_ranker() { return category_ranker_.get(); }
 
+  ContextualSuggestionsSource* contextual_suggestions_source() {
+    DCHECK(contextual_suggestions_source_);
+    return contextual_suggestions_source_.get();
+  }
+
  private:
   friend class ContentSuggestionsServiceTest;