Trigger the Snippets Scheduler when Resuming Activities

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

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetsBridge.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetsBridge.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetsBridge.java
index 40364ba072b9a2b33d74887057ac8655fbe7a81e..3f3e4e23a59bf3590a787c8d831418b16bbeffe0 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetsBridge.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetsBridge.java
@@ -4,8 +4,11 @@
 
 package org.chromium.chrome.browser.ntp.snippets;
 
+import android.app.Activity;
 import android.graphics.Bitmap;
 
+import org.chromium.base.ActivityState;
+import org.chromium.base.ApplicationStatus;
 import org.chromium.base.Callback;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.chrome.browser.ntp.cards.SuggestionsCategoryInfo;
@@ -171,6 +174,22 @@ public class SnippetsBridge implements SuggestionsSource {
         nativeOnMoreButtonClicked(mNativeSnippetsBridge, category, position);
     }
 
+    /**
+     * Returns a listener creating a bridge to propagate the activity state changes.
+     */
+    public static ApplicationStatus.ActivityStateListener makeActivityStateListener() {
+        return new ApplicationStatus.ActivityStateListener() {
+            @Override
+            public void onActivityStateChange(Activity activity, int newState) {
+                if (newState == ActivityState.RESUMED) {
+                    SnippetsBridge snippetsBridge =
+                            new SnippetsBridge(Profile.getLastUsedProfile());
+                    snippetsBridge.onActivityResumed();
+                }
+            }
+        };
+    }
+
     public static void onSuggestionTargetVisited(int category, long visitTimeMs) {
         nativeOnSuggestionTargetVisited(category, visitTimeMs);
     }
@@ -200,6 +219,11 @@ public class SnippetsBridge implements SuggestionsSource {
         nativeFetch(mNativeSnippetsBridge, category, displayedSuggestionIds);
     }
 
+    private void onActivityResumed() {
+        assert mNativeSnippetsBridge != 0;
+        nativeOnActivityResumed(mNativeSnippetsBridge);
+    }
+
     @CalledByNative
     private static List<SnippetArticle> createSuggestionList() {
         return new ArrayList<>();
@@ -304,6 +328,7 @@ public class SnippetsBridge implements SuggestionsSource {
             long nativeNTPSnippetsBridge, int category, int position);
     private native void nativeOnMoreButtonClicked(
             long nativeNTPSnippetsBridge, int category, int position);
+    private native void nativeOnActivityResumed(long nativeNTPSnippetsBridge);
     private static native void nativeOnSuggestionTargetVisited(int category, long visitTimeMs);
     private native void nativeSetObserver(long nativeNTPSnippetsBridge, SnippetsBridge bridge);
 }