[Enhanced Bookmark]Rewrite initialization logic

chrome/android/java/src/org/chromium/chrome/browser/bookmark/BookmarksBridge.java

 // Copyright 2013 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.
 
 package org.chromium.chrome.browser.bookmark;
 
 import android.util.Pair;
 
 import org.chromium.base.ObserverList;
 import org.chromium.base.VisibleForTesting;
@@ skipping 189 matching lines @@
     }
 
     /**
      * @return Whether or not the underlying bookmark model is loaded.
      */
     public boolean isBookmarkModelLoaded() {
         return mIsNativeBookmarkModelLoaded;
     }
 
     /**
+     * Schedules a runnable to run after the bookmark model is loaded. If the
+     * model is already loaded, executes the runnable immediately.
+     * @return Whether the given runnable is executed synchronously.
+     */
+    public boolean runAfterBookmarkModelLoaded(final Runnable runnable) {
+        if (isBookmarkModelLoaded()) {
+            runnable.run();
+            return true;
+        }
+        addObserver(new BookmarkModelObserver() {
+            @Override
+            public void bookmarkModelLoaded() {
+                removeObserver(this);
+                runnable.run();
+            }
+            @Override
+            public void bookmarkModelChanged() {
+            }
+        });
+        return false;
+    }
+
+    /**
      * @return A BookmarkItem instance for the given BookmarkId.
      *         <code>null</code> if it doesn't exist.
      */
     public BookmarkItem getBookmarkById(BookmarkId id) {
         assert mIsNativeBookmarkModelLoaded;
         return nativeGetBookmarkByID(mNativeBookmarksBridge, id.getId(), id.getType());
     }
 
     /**
      * @return All the permanent nodes.
@@ skipping 656 matching lines @@
                 case GET_CURRENT_FOLDER_HIERARCHY:
                     mHandler.getCurrentFolderHierarchy(mFolderId, mCallback);
                     break;
                 default:
                     assert false;
                     break;
             }
         }
     }
 }