[Offline pages] Detecting missing offline copy

chrome/android/java/src/org/chromium/chrome/browser/offlinepages/OfflinePageBridge.java

Index: chrome/android/java/src/org/chromium/chrome/browser/offlinepages/OfflinePageBridge.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/offlinepages/OfflinePageBridge.java b/chrome/android/java/src/org/chromium/chrome/browser/offlinepages/OfflinePageBridge.java
index 5a66045246a828ae40c1df0fe5e2add350ff975d..3676d4761588d6b91decda1881b6bf6081d47e40 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/offlinepages/OfflinePageBridge.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/offlinepages/OfflinePageBridge.java
@@ -13,6 +13,7 @@ import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.chrome.browser.BookmarksBridge;
 import org.chromium.chrome.browser.profiles.Profile;
 import org.chromium.components.bookmarks.BookmarkId;
+import org.chromium.components.bookmarks.BookmarkType;
 import org.chromium.content_public.browser.WebContents;
 
 import java.util.ArrayList;
@@ -64,13 +65,19 @@ public final class OfflinePageBridge {
     }
 
     /**
-     * Interface that provides listeners to be notified of changes to the offline page model.
+     *  Base observer class listeners to be notified of changes to the offline page model.
      */
-    public interface OfflinePageModelObserver {
+    public abstract static class OfflinePageModelObserver {
         /**
          * Called when the native side of offline pages is loaded and now in usable state.
          */
-        void offlinePageModelLoaded();
+        public void offlinePageModelLoaded() {}
+
+        /**
+         * Called when an offline page is deleted.
+         * @param bookmarkId A bookmark ID of the deleted offline page.
+         */
+        public void offlinePageDeleted(BookmarkId bookmarkId) {}
     }
 
     private static int getFreeSpacePercentage() {
@@ -235,6 +242,13 @@ public final class OfflinePageBridge {
         return result;
     }
 
+    /**
+     * Starts a check of offline page metadata, e.g. are all offline copies present.
+     */
+    public void checkOfflinePageMetadata() {
+        nativeCheckMetadataConsistency(mNativeOfflinePageBridge);
+    }
+
     @CalledByNative
     private void offlinePageModelLoaded() {
         mIsNativeOfflinePageModelLoaded = true;
@@ -244,6 +258,14 @@ public final class OfflinePageBridge {
     }
 
     @CalledByNative
+    private void offlinePageDeleted(long bookmarkId) {
+        BookmarkId id = new BookmarkId(bookmarkId, BookmarkType.NORMAL);
+        for (OfflinePageModelObserver observer : mObservers) {
+            observer.offlinePageDeleted(id);
+        }
+    }
+
+    @CalledByNative
     private static void createOfflinePageAndAddToList(List<OfflinePageItem> offlinePagesList,
             String url, long bookmarkId, String offlineUrl, long fileSize, int accessCount) {
         offlinePagesList.add(createOfflinePageItem(url, bookmarkId, offlineUrl, fileSize,
@@ -273,4 +295,5 @@ public final class OfflinePageBridge {
             long nativeOfflinePageBridge, DeletePageCallback callback, long[] bookmarkIds);
     private native void nativeGetPagesToCleanUp(
             long nativeOfflinePageBridge, List<OfflinePageItem> offlinePages);
+    private native void nativeCheckMetadataConsistency(long nativeOfflinePageBridge);
 }