[Enhanced Bookmark]Rewrite initialization logic

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

Index: chrome/android/java/src/org/chromium/chrome/browser/bookmark/BookmarksBridge.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/bookmark/BookmarksBridge.java b/chrome/android/java/src/org/chromium/chrome/browser/bookmark/BookmarksBridge.java
index f0c1a978799229ae4b2e77285ac99fd1371d8e25..34f842f7173180160dbf0be881cdf8d9403a2db5 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/bookmark/BookmarksBridge.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/bookmark/BookmarksBridge.java
@@ -207,6 +207,29 @@ public class BookmarksBridge {
     }
 
     /**
+     * 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.
      */