🏡 Display Snackbar when user triggered fetch fails.

When the user triggers a fetch through the more button, if the fetch
fails, display a Snackbar. Ideally in the future we can offer the user
information specific to how it failed and actions to remedy it.

Bug: 663376, 765603
Change-Id: I12fb27631454fb015803ae4a24a3d69c0a13357c
Reviewed-on: https://chromium-review.googlesource.com/671269Reviewed-by: Bernhard Bauer <bauerb@chromium.org>
Reviewed-by: Jan Krcal <jkrcal@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Peter Conn <peconn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#504427}

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPage.java

@@ -33,6 +33,7 @@ import org.chromium.chrome.browser.ntp.snippets.SuggestionsSource;
 import org.chromium.chrome.browser.profiles.Profile;
 import org.chromium.chrome.browser.search_engines.TemplateUrlService;
 import org.chromium.chrome.browser.search_engines.TemplateUrlService.TemplateUrlServiceObserver;
+import org.chromium.chrome.browser.snackbar.SnackbarManager;
 import org.chromium.chrome.browser.suggestions.SuggestionsDependencyFactory;
 import org.chromium.chrome.browser.suggestions.SuggestionsEventReporter;
 import org.chromium.chrome.browser.suggestions.SuggestionsMetrics;
@@ -159,9 +160,10 @@ public class NewTabPage
         public NewTabPageManagerImpl(SuggestionsSource suggestionsSource,
                 SuggestionsEventReporter eventReporter,
                 SuggestionsNavigationDelegate navigationDelegate, Profile profile,
-                NativePageHost nativePageHost, DiscardableReferencePool referencePool) {
+                NativePageHost nativePageHost, DiscardableReferencePool referencePool,
+                SnackbarManager snackbarManager) {
             super(suggestionsSource, eventReporter, navigationDelegate, profile, nativePageHost,
-                    referencePool);
+                    referencePool, snackbarManager);
         }
 
         @Override
@@ -265,7 +267,8 @@ public class NewTabPage
                 new SuggestionsNavigationDelegateImpl(
                         activity, profile, nativePageHost, tabModelSelector);
         mNewTabPageManager = new NewTabPageManagerImpl(suggestionsSource, eventReporter,
-                navigationDelegate, profile, nativePageHost, activity.getReferencePool());
+                navigationDelegate, profile, nativePageHost, activity.getReferencePool(),
+                activity.getSnackbarManager());
         mTileGroupDelegate = new NewTabPageTileGroupDelegate(activity, profile, navigationDelegate);
 
         mTitle = activity.getResources().getString(R.string.button_new_tab);

chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/ActionItem.java

@@ -6,6 +6,7 @@ package org.chromium.chrome.browser.ntp.cards;
 
 import android.support.annotation.IntDef;
 import android.support.annotation.LayoutRes;
+import android.support.annotation.Nullable;
 import android.view.View;
 import android.widget.Button;
 
@@ -14,6 +15,8 @@ import org.chromium.chrome.R;
 import org.chromium.chrome.browser.metrics.ImpressionTracker;
 import org.chromium.chrome.browser.ntp.ContextMenuManager;
 import org.chromium.chrome.browser.ntp.snippets.CategoryInt;
+import org.chromium.chrome.browser.snackbar.Snackbar;
+import org.chromium.chrome.browser.snackbar.SnackbarManager;
 import org.chromium.chrome.browser.suggestions.ContentSuggestionsAdditionalAction;
 import org.chromium.chrome.browser.suggestions.SuggestionsMetrics;
 import org.chromium.chrome.browser.suggestions.SuggestionsRanker;
@@ -114,8 +117,14 @@ public class ActionItem extends OptionalLeaf {
         return mState;
     }
 
+    /**
+     * Perform the Action associated with this ActionItem.
+     * @param uiDelegate A {@link SuggestionsUiDelegate} to provide context.
+     * @param onFailure A {@link Runnable} that will be run if the action was to fetch more
+     *                  suggestions but that action failed.
+     */
     @VisibleForTesting
-    void performAction(SuggestionsUiDelegate uiDelegate) {
+    void performAction(SuggestionsUiDelegate uiDelegate, @Nullable Runnable onFailure) {
         assert mState == State.BUTTON;
 
         uiDelegate.getEventReporter().onMoreButtonClicked(this);
@@ -127,7 +136,7 @@ public class ActionItem extends OptionalLeaf {
                 mCategoryInfo.performViewAllAction(uiDelegate.getNavigationDelegate());
                 return;
             case ContentSuggestionsAdditionalAction.FETCH:
-                mParentSection.fetchSuggestions();
+                mParentSection.fetchSuggestions(onFailure);
                 return;
             case ContentSuggestionsAdditionalAction.NONE:
             default:
@@ -141,15 +150,18 @@ public class ActionItem extends OptionalLeaf {
         private ActionItem mActionListItem;
         private final ProgressIndicatorView mProgressIndicator;
         private final Button mButton;
+        private final SuggestionsUiDelegate mUiDelegate;
 
         public ViewHolder(SuggestionsRecyclerView recyclerView,
-                ContextMenuManager contextMenuManager, SuggestionsUiDelegate uiDelegate,
+                ContextMenuManager contextMenuManager, final SuggestionsUiDelegate uiDelegate,
                 UiConfig uiConfig) {
             super(getLayout(), recyclerView, uiConfig, contextMenuManager);
 
             mProgressIndicator = itemView.findViewById(R.id.progress_indicator);
             mButton = itemView.findViewById(R.id.action_button);
-            mButton.setOnClickListener(v -> mActionListItem.performAction(uiDelegate));
+            mUiDelegate = uiDelegate;
+            mButton.setOnClickListener(v -> mActionListItem.performAction(uiDelegate,
+                    this::showFetchFailureSnackbar));
 
             new ImpressionTracker(itemView, () -> {
                 if (mActionListItem != null && !mActionListItem.mImpressionTracked) {
@@ -159,6 +171,15 @@ public class ActionItem extends OptionalLeaf {
             });
         }
 
+        private void showFetchFailureSnackbar() {
+            mUiDelegate.getSnackbarManager().showSnackbar(Snackbar.make(
+                    itemView.getResources().getString(R.string.ntp_suggestions_fetch_failed),
+                    new SnackbarManager.SnackbarController() { },
+                    Snackbar.TYPE_ACTION,
+                    Snackbar.UMA_SNIPPET_FETCH_FAILED)
+            );
+        }
+
         public void onBindViewHolder(ActionItem item) {
             super.onBindViewHolder();
             mActionListItem = item;

chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/SectionList.java

@@ -244,7 +244,10 @@ public class SectionList
         } else if (supportingSections.get(0).isLoading()) {
             Log.d(TAG, "SectionList.fetchMore - Supporting section is already loading.");
         } else {
-            supportingSections.get(0).fetchSuggestions();
+            // Fetch more is called when the user does not explicitly trigger a fetch (eg, the user
+            // scrolls down). In this case we don't inform the user of a failure, hence the null
+            // parameter.
+            supportingSections.get(0).fetchSuggestions(null);
         }
     }
 

chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/SuggestionsSection.java

@@ -534,8 +534,12 @@ public class SuggestionsSection extends InnerNode {
 
         return true;
     }
-    /** Fetches additional suggestions only for this section. */
-    public void fetchSuggestions() {
+
+    /**
+     * Fetches additional suggestions only for this section.
+     * @param onFailure A {@link Runnable} that will be run if the fetch fails.
+     */
+    public void fetchSuggestions(@Nullable final Runnable onFailure) {
         assert !isLoading();
 
         if (getSuggestionsCount() == 0 && getCategoryInfo().isRemote()) {
@@ -546,12 +550,19 @@ public class SuggestionsSection extends InnerNode {
         }
 
         mMoreButton.updateState(ActionItem.State.LOADING);
-        mSuggestionsSource.fetchSuggestions(
-                mCategoryInfo.getCategory(), getDisplayedSuggestionIds(), additionalSuggestions -> {
+        mSuggestionsSource.fetchSuggestions(mCategoryInfo.getCategory(),
+                getDisplayedSuggestionIds(),
+                suggestions -> {  /* successCallback */
+                    if (!isAttached()) return; // The section has been dismissed.
+
+                    mMoreButton.updateState(ActionItem.State.BUTTON);
+                    appendSuggestions(suggestions, /* keepSectionSize = */ false);
+                },
+                () -> {  /* failureRunnable */
                     if (!isAttached()) return; // The section has been dismissed.
 
-                    appendSuggestions(additionalSuggestions, /* keepSectionSize = */ false);
                     mMoreButton.updateState(ActionItem.State.BUTTON);
+                    if (onFailure != null) onFailure.run();
                 });
     }
 

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

@@ -186,9 +186,13 @@ public class SnippetsBridge implements SuggestionsSource {
 
     @Override
     public void fetchSuggestions(@CategoryInt int category, String[] displayedSuggestionIds,
-            Callback<List<SnippetArticle>> callback) {
+            Callback<List<SnippetArticle>> successCallback, Runnable failureRunnable) {
         assert mNativeSnippetsBridge != 0;
-        nativeFetch(mNativeSnippetsBridge, category, displayedSuggestionIds, callback);
+        // We have nice JNI support for Callbacks but not for Runnables, so wrap the Runnable
+        // in a Callback and discard the parameter.
+        // TODO(peconn): Use a Runnable here if they get nice JNI support.
+        nativeFetch(mNativeSnippetsBridge, category, displayedSuggestionIds, successCallback,
+                ignored -> failureRunnable.run());
     }
 
     @CalledByNative
@@ -281,7 +285,8 @@ public class SnippetsBridge implements SuggestionsSource {
             String idWithinCategory, int minimumSizePx, int desiredSizePx,
             Callback<Bitmap> callback);
     private native void nativeFetch(long nativeNTPSnippetsBridge, int category,
-            String[] knownSuggestions, Callback<List<SnippetArticle>> callback);
+            String[] knownSuggestions, Callback<List<SnippetArticle>> successCallback,
+            Callback<Integer> failureCallback);
     private native void nativeFetchContextualSuggestions(
             long nativeNTPSnippetsBridge, String url, Callback<List<SnippetArticle>> callback);
     private native void nativeFetchContextualSuggestionImage(long nativeNTPSnippetsBridge,

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

@@ -100,10 +100,11 @@ public interface SuggestionsSource {
      * Fetches new suggestions.
      * @param category the category to fetch new suggestions for.
      * @param displayedSuggestionIds ids of suggestions already known and that we want to keep.
-     * @param callback The callback to run with the received suggestions.
+     * @param successCallback The callback to run with the received suggestions.
+     * @param failureRunnable The runnable to be run if the fetch fails.
      */
     void fetchSuggestions(@CategoryInt int category, String[] displayedSuggestionIds,
-            Callback<List<SnippetArticle>> callback);
+            Callback<List<SnippetArticle>> successCallback, Runnable failureRunnable);
 
     /**
      * Fetches suggestions related to the provided URL.

chrome/android/java/src/org/chromium/chrome/browser/snackbar/Snackbar.java

@@ -58,6 +58,7 @@ public class Snackbar {
     public static final int UMA_TRANSLATE_ALWAYS = 18;
     public static final int UMA_TRANSLATE_NEVER = 19;
     public static final int UMA_TRANSLATE_NEVER_SITE = 20;
+    public static final int UMA_SNIPPET_FETCH_FAILED = 21;
 
     private SnackbarController mController;
     private CharSequence mText;

chrome/android/java/src/org/chromium/chrome/browser/snackbar/SnackbarManager.java

@@ -48,13 +48,13 @@ public class SnackbarManager implements OnClickListener, InfoBarContainer.InfoBa
          * Called when the user clicks the action button on the snackbar.
          * @param actionData Data object passed when showing this specific snackbar.
          */
-        void onAction(Object actionData);
+        default void onAction(Object actionData) { }
 
         /**
          * Called when the snackbar is dismissed by tiemout or UI enviroment change.
          * @param actionData Data object associated with the dismissed snackbar entry.
          */
-        void onDismissNoAction(Object actionData);
+        default void onDismissNoAction(Object actionData) { }
     }
 
     private static final int DEFAULT_SNACKBAR_DURATION_MS = 3000;

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

@@ -89,7 +89,7 @@ public class SuggestionsBottomSheetContent implements BottomSheet.BottomSheetCon
                 new TileGroupDelegateImpl(activity, profile, navigationDelegate, snackbarManager);
         mSuggestionsUiDelegate = new SuggestionsUiDelegateImpl(
                 depsFactory.createSuggestionSource(profile), depsFactory.createEventReporter(),
-                navigationDelegate, profile, sheet, activity.getReferencePool());
+                navigationDelegate, profile, sheet, activity.getReferencePool(), snackbarManager);
 
         mView = LayoutInflater.from(activity).inflate(
                 R.layout.suggestions_bottom_sheet_content, null);

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

@@ -6,6 +6,7 @@ package org.chromium.chrome.browser.suggestions;
 
 import org.chromium.base.DiscardableReferencePool;
 import org.chromium.chrome.browser.ntp.snippets.SuggestionsSource;
+import org.chromium.chrome.browser.snackbar.SnackbarManager;
 
 /**
  * Interface between the suggestion surface and the rest of the browser.
@@ -27,9 +28,12 @@ public interface SuggestionsUiDelegate {
     /** Convenience method to access the {@link SuggestionsNavigationDelegate}. */
     SuggestionsNavigationDelegate getNavigationDelegate();
 
-    /** Convenience method to access the {@link ImageFetcher} */
+    /** Convenience method to access the {@link ImageFetcher}. */
     ImageFetcher getImageFetcher();
 
+    /** Convenience method to access the {@link SnackbarManager}. */
+    SnackbarManager getSnackbarManager();
+
     /**
      * @return The reference pool to use for large objects that should be dropped under
      * memory pressure.

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

@@ -10,6 +10,7 @@ import org.chromium.base.DiscardableReferencePool;
 import org.chromium.chrome.browser.NativePageHost;
 import org.chromium.chrome.browser.ntp.snippets.SuggestionsSource;
 import org.chromium.chrome.browser.profiles.Profile;
+import org.chromium.chrome.browser.snackbar.SnackbarManager;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -25,6 +26,7 @@ public class SuggestionsUiDelegateImpl implements SuggestionsUiDelegate {
     private final SuggestionsNavigationDelegate mSuggestionsNavigationDelegate;
     private final NativePageHost mHost;
     private final ImageFetcher mImageFetcher;
+    private final SnackbarManager mSnackbarManager;
 
     private final DiscardableReferencePool mReferencePool;
 
@@ -33,12 +35,13 @@ public class SuggestionsUiDelegateImpl implements SuggestionsUiDelegate {
     public SuggestionsUiDelegateImpl(SuggestionsSource suggestionsSource,
             SuggestionsEventReporter eventReporter,
             SuggestionsNavigationDelegate navigationDelegate, Profile profile, NativePageHost host,
-            DiscardableReferencePool referencePool) {
+            DiscardableReferencePool referencePool, SnackbarManager snackbarManager) {
         mSuggestionsSource = suggestionsSource;
         mSuggestionsRanker = new SuggestionsRanker();
         mSuggestionsEventReporter = eventReporter;
         mSuggestionsNavigationDelegate = navigationDelegate;
         mImageFetcher = new ImageFetcher(suggestionsSource, profile, referencePool, host);
+        mSnackbarManager = snackbarManager;
 
         mHost = host;
         mReferencePool = referencePool;
@@ -66,6 +69,11 @@ public class SuggestionsUiDelegateImpl implements SuggestionsUiDelegate {
         return mSuggestionsNavigationDelegate;
     }
 
+    @Override
+    public SnackbarManager getSnackbarManager() {
+        return mSnackbarManager;
+    }
+
     @Override
     public ImageFetcher getImageFetcher() {
         return mImageFetcher;

chrome/android/java/strings/android_chrome_strings.grd

@@ -2406,6 +2406,9 @@ To obtain new licenses, connect to the internet and play your downloaded content
       <message name="IDS_NTP_ALL_DISMISSED_BODY_TEXT_MODERN" desc="Body text shown on the New Tab Page when all suggested content has been dismissed. The message refers to the &quot;More&quot; button to fetch more suggestions.">
         Tap More to get articles
       </message>
+      <message name="IDS_NTP_SUGGESTIONS_FETCH_FAILED" desc="Snackbar text shown when the user presses the More button to get more suggestions, but this fails (eg, no internet connectivity).">
+        Unable to get suggestions
+      </message>
       <message name="IDS_NTP_ALL_DISMISSED_REFRESH" desc="Text label for button to refresh the New Tab Page when all suggested content has been dismissed. [CHAR-LIMIT=20]">
         Refresh
       </message>

chrome/android/javatests/src/org/chromium/chrome/browser/ntp/snippets/ArticleSnippetsTest.java

@@ -52,6 +52,7 @@ import org.chromium.chrome.browser.preferences.ChromePreferenceManager;
 import org.chromium.chrome.browser.signin.DisplayableProfileData;
 import org.chromium.chrome.browser.signin.SigninAccessPoint;
 import org.chromium.chrome.browser.signin.SigninPromoController;
+import org.chromium.chrome.browser.snackbar.SnackbarManager;
 import org.chromium.chrome.browser.suggestions.ContentSuggestionsAdditionalAction;
 import org.chromium.chrome.browser.suggestions.DestructionObserver;
 import org.chromium.chrome.browser.suggestions.ImageFetcher;
@@ -463,6 +464,11 @@ public class ArticleSnippetsTest {
         public ImageFetcher getImageFetcher() {
             return mImageFetcher;
         }
+
+        @Override
+        public SnackbarManager getSnackbarManager() {
+            return mActivityTestRule.getActivity().getSnackbarManager();
+        }
     }
 
     private class MockImageFetcher extends ImageFetcher {

chrome/android/javatests/src/org/chromium/chrome/browser/suggestions/TileGridLayoutTest.java

@@ -339,7 +339,7 @@ public class TileGridLayoutTest {
         SuggestionsUiDelegate uiDelegate = new SuggestionsUiDelegateImpl(
                 mSuggestionsDeps.getFactory().createSuggestionSource(null),
                 mSuggestionsDeps.getFactory().createEventReporter(), null, profile, null,
-                activity.getChromeApplication().getReferencePool());
+                activity.getChromeApplication().getReferencePool(), activity.getSnackbarManager());
 
         OfflinePageBridge opb = OfflinePageBridge.getForProfile(profile);
         TileGroup.Delegate delegate = new TileGroupDelegateImpl(activity, profile, null, null);

chrome/android/junit/src/org/chromium/chrome/browser/ntp/cards/SuggestionsSectionTest.java

@@ -34,6 +34,7 @@ import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
 import org.robolectric.RuntimeEnvironment;
@@ -430,6 +431,7 @@ public class SuggestionsSectionTest {
     @Feature({"Ntp"})
     public void testFetchMoreProgressDisplay() {
         final int suggestionCount = 3;
+        // Spy so that VerifyAction can check methods being called.
         SuggestionsCategoryInfo info =
                 spy(new CategoryInfoBuilder(TEST_CATEGORY_ID)
                                 .withAction(ContentSuggestionsAdditionalAction.FETCH)
@@ -459,12 +461,10 @@ public class SuggestionsSectionTest {
     @Feature({"Ntp"})
     public void testFetchMoreAfterDismissAll() {
         final int suggestionCount = 10;
-        SuggestionsCategoryInfo info =
-                spy(new CategoryInfoBuilder(REMOTE_TEST_CATEGORY)
+        SuggestionsSection section = createSection(new CategoryInfoBuilder(REMOTE_TEST_CATEGORY)
                 .withAction(ContentSuggestionsAdditionalAction.FETCH)
                 .showIfEmpty()
                 .build());
-        SuggestionsSection section = createSection(info);
         section.setStatus(CategoryStatus.AVAILABLE);
         section.appendSuggestions(createDummySuggestions(suggestionCount, REMOTE_TEST_CATEGORY),
                 /*keepSectionSize=*/true);
@@ -485,7 +485,7 @@ public class SuggestionsSectionTest {
 
         // Tap the button -- we handle this case explicitly here to avoid complexity in
         // verifyAction().
-        section.getActionItemForTesting().performAction(mUiDelegate);
+        section.getActionItemForTesting().performAction(mUiDelegate, null);
         verify(mUiDelegate.getSuggestionsSource(), times(1)).fetchRemoteSuggestions();
 
         // Simulate the arrival of new data.
@@ -501,6 +501,40 @@ public class SuggestionsSectionTest {
         assertFalse(section.isDataStale());
     }
 
+    @Test
+    @Feature("Ntp")
+    public void testFetchMoreFailure() {
+        SuggestionsSection section = createSection(new CategoryInfoBuilder(REMOTE_TEST_CATEGORY)
+                .withAction(ContentSuggestionsAdditionalAction.FETCH)
+                .showIfEmpty()
+                .build());
+        section.setStatus(CategoryStatus.AVAILABLE);
+        section.appendSuggestions(createDummySuggestions(10, REMOTE_TEST_CATEGORY),
+                /*keepSectionSize=*/true);
+        assertEquals(ActionItem.State.BUTTON, section.getActionItemForTesting().getState());
+        assertTrue(section.getCategoryInfo().isRemote());
+
+        // Tap the button, providing a Runnable for when it fails.
+        Runnable sectionOnFailureRunnable = mock(Runnable.class);
+        section.getActionItemForTesting().performAction(mUiDelegate, sectionOnFailureRunnable);
+
+        // Ensure the tap leads to a fetch request on the source with a (potentially different)
+        // failure Runnable.
+        ArgumentCaptor<Runnable> sourceOnFailureRunnable = ArgumentCaptor.forClass(Runnable.class);
+        verify(mUiDelegate.getSuggestionsSource(), times(1)).fetchSuggestions(
+                eq(REMOTE_TEST_CATEGORY), any(), any(), sourceOnFailureRunnable.capture());
+
+        // Ensure the progress spinner is shown.
+        assertEquals(ActionItem.State.LOADING, section.getActionItemForTesting().getState());
+
+        // Simulate a failure.
+        sourceOnFailureRunnable.getValue().run();
+
+        // Ensure we're back to the button and the section's failure runnable has been run.
+        assertEquals(ActionItem.State.BUTTON, section.getActionItemForTesting().getState());
+        verify(sectionOnFailureRunnable, times(1)).run();
+    }
+
     /**
      * Tests that the UI updates on updated suggestions.
      */
@@ -908,7 +942,7 @@ public class SuggestionsSectionTest {
     private void verifyAction(
             SuggestionsSection section, @ContentSuggestionsAdditionalAction int action) {
         if (action != ContentSuggestionsAdditionalAction.NONE) {
-            section.getActionItemForTesting().performAction(mUiDelegate);
+            section.getActionItemForTesting().performAction(mUiDelegate, null);
         }
 
         verify(section.getCategoryInfo(),
@@ -918,6 +952,7 @@ public class SuggestionsSectionTest {
         // noinspection unchecked -- See https://crbug.com/740162 for rationale.
         verify(mUiDelegate.getSuggestionsSource(),
                 (action == ContentSuggestionsAdditionalAction.FETCH ? times(1) : never()))
-                .fetchSuggestions(anyInt(), any(String[].class), any(Callback.class));
+                .fetchSuggestions(anyInt(), any(String[].class), any(Callback.class),
+                        any(Runnable.class));
     }
 }

chrome/browser/android/ntp/ntp_snippets_bridge.cc

@@ -283,8 +283,10 @@ void NTPSnippetsBridge::Fetch(
     const JavaParamRef<jobject>& obj,
     jint j_category_id,
     const JavaParamRef<jobjectArray>& j_displayed_suggestions,
-    const JavaParamRef<jobject>& j_callback) {
-  ScopedJavaGlobalRef<jobject> callback(j_callback);
+    const JavaParamRef<jobject>& j_success_callback,
+    const JavaParamRef<jobject>& j_failure_callback) {
+  ScopedJavaGlobalRef<jobject> success_callback(j_success_callback);
+  ScopedJavaGlobalRef<jobject> failure_callback(j_failure_callback);
   std::vector<std::string> known_suggestion_ids;
   AppendJavaStringArrayToStringVector(env, j_displayed_suggestions,
                                       &known_suggestion_ids);
@@ -295,7 +297,8 @@ void NTPSnippetsBridge::Fetch(
       std::set<std::string>(known_suggestion_ids.begin(),
                             known_suggestion_ids.end()),
       base::Bind(&NTPSnippetsBridge::OnSuggestionsFetched,
-                 weak_ptr_factory_.GetWeakPtr(), callback, category));
+                 weak_ptr_factory_.GetWeakPtr(), success_callback,
+                 failure_callback, category));
 }
 
 void NTPSnippetsBridge::FetchContextualSuggestions(
@@ -418,14 +421,22 @@ void NTPSnippetsBridge::OnImageFetched(ScopedJavaGlobalRef<jobject> callback,
 }
 
 void NTPSnippetsBridge::OnSuggestionsFetched(
-    const ScopedJavaGlobalRef<jobject>& callback,
+    const ScopedJavaGlobalRef<jobject>& success_callback,
+    const ScopedJavaGlobalRef<jobject>& failure_callback,
     Category category,
     ntp_snippets::Status status,
     std::vector<ContentSuggestion> suggestions) {
   // TODO(fhorschig, dgn): Allow refetch or show notification acc. to status.
   JNIEnv* env = AttachCurrentThread();
-  RunCallbackAndroid(callback,
+  if (status.IsSuccess()) {
+    RunCallbackAndroid(success_callback,
         ToJavaSuggestionList(env, category, suggestions));
+  } else {
+    // The second parameter here means nothing - it was more convenient to pass
+    // a Callback (which has 1 parameter) over to the native side than a
+    // Runnable (which has no parameters). We ignore the parameter Java-side.
+    RunCallbackAndroid(failure_callback, 0);
+  }
 }
 
 void NTPSnippetsBridge::OnContextualSuggestionsFetched(

chrome/browser/android/ntp/ntp_snippets_bridge.h

@@ -77,7 +77,8 @@ class NTPSnippetsBridge
       const base::android::JavaParamRef<jobject>& obj,
       jint j_category_id,
       const base::android::JavaParamRef<jobjectArray>& j_displayed_suggestions,
-      const base::android::JavaParamRef<jobject>& j_callback);
+      const base::android::JavaParamRef<jobject>& j_fetch_success_callback,
+      const base::android::JavaParamRef<jobject>& j_fetch_failure_callback);
 
   void FetchContextualSuggestions(
       JNIEnv* env,
@@ -128,7 +129,8 @@ class NTPSnippetsBridge
   void OnImageFetched(base::android::ScopedJavaGlobalRef<jobject> callback,
                       const gfx::Image& image);
   void OnSuggestionsFetched(
-      const base::android::ScopedJavaGlobalRef<jobject>& callback,
+      const base::android::ScopedJavaGlobalRef<jobject>& success_callback,
+      const base::android::ScopedJavaGlobalRef<jobject>& failure_callback,
       ntp_snippets::Category category,
       ntp_snippets::Status status,
       std::vector<ntp_snippets::ContentSuggestion> suggestions);

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

@@ -243,7 +243,8 @@ public class FakeSuggestionsSource implements SuggestionsSource {
 
     @Override
     public void fetchSuggestions(@CategoryInt int category, String[] displayedSuggestionIds,
-            Callback<List<SnippetArticle>> callback) {}
+            Callback<List<SnippetArticle>> successCallback, Runnable failureRunnable) {
+    }
 
     @Override
     public void fetchContextualSuggestions(String url, Callback<List<SnippetArticle>> callback) {

tools/metrics/histograms/enums.xml

@@ -35729,6 +35729,7 @@ from previous Chrome versions.
   <int value="18" label="TRANSLATE_ALWAYS"/>
   <int value="19" label="TRANSLATE_NEVER"/>
   <int value="20" label="TRANSLATE_NEVER_SITE"/>
+  <int value="21" label="SNIPPET_FETCH_FAILED"/>
 </enum>
 
 <enum name="SnippetOpenMethod">