Add an about flag to toggle the visibility of "All bookmarks"

chrome/android/java/src/org/chromium/chrome/browser/bookmarks/BookmarkUIState.java

Index: chrome/android/java/src/org/chromium/chrome/browser/bookmarks/BookmarkUIState.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/bookmarks/BookmarkUIState.java b/chrome/android/java/src/org/chromium/chrome/browser/bookmarks/BookmarkUIState.java
index ec8851c19b9ae701bfe25f90413af925441e513d..27ef20018abb117406ac1268c329c3ff97c41beb 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/bookmarks/BookmarkUIState.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/bookmarks/BookmarkUIState.java
@@ -7,6 +7,7 @@ package org.chromium.chrome.browser.bookmarks;
 import android.net.Uri;
 import android.text.TextUtils;
 
+import org.chromium.base.VisibleForTesting;
 import org.chromium.chrome.browser.UrlConstants;
 import org.chromium.components.bookmarks.BookmarkId;
 
@@ -20,7 +21,6 @@ class BookmarkUIState {
     static final int STATE_LOADING = 1;
     static final int STATE_ALL_BOOKMARKS = 2;
     static final int STATE_FOLDER = 3;
-    private static final int STATE_INVALID = 0;
 
     /**
      * One of the STATE_* constants.
@@ -36,53 +36,48 @@ class BookmarkUIState {
         return state;
     }
 
+    /**
+     * Depending on experiments we run, "all bookmarks" might be redirected to the default folder.
+     */
     static BookmarkUIState createAllBookmarksState(BookmarkModel bookmarkModel) {
-        return createStateFromUrl(Uri.parse(UrlConstants.BOOKMARKS_URL), bookmarkModel);
+        if (!BookmarkUtils.isAllBookmarksViewEnabled()) {
+            return createFolderState(bookmarkModel.getDefaultFolder(), null);
+        }
+        BookmarkUIState state = new BookmarkUIState();
+        state.mState = STATE_ALL_BOOKMARKS;
+        state.mUrl = UrlConstants.BOOKMARKS_URL;
+        return state;
     }
 
-    static BookmarkUIState createFolderState(BookmarkId folder,
-            BookmarkModel bookmarkModel) {
-        return createStateFromUrl(createFolderUrl(folder), bookmarkModel);
+    static BookmarkUIState createFolderState(BookmarkId folder, BookmarkModel bookmarkModel) {
+        if (folder == null) return createAllBookmarksState(bookmarkModel);
+        BookmarkUIState state = new BookmarkUIState();
+        state.mState = STATE_FOLDER;
+        state.mUrl = UrlConstants.BOOKMARKS_FOLDER_URL + folder.toString();
+        state.mFolder = folder;
+        return state;
     }
 
     /**
-     * @see #createStateFromUrl(Uri, BookmarkModel)
+     * Parses the url and generates the corresponding state.
      */
     static BookmarkUIState createStateFromUrl(String url, BookmarkModel bookmarkModel) {
-        return createStateFromUrl(Uri.parse(url), bookmarkModel);
-    }
-
-    /**
-     * @return A state corresponding to the URI object. If the URI is not valid,
-     *         return all_bookmarks.
-     */
-    static BookmarkUIState createStateFromUrl(Uri uri, BookmarkModel bookmarkModel) {
-        BookmarkUIState state = new BookmarkUIState();
-        state.mState = STATE_INVALID;
-        state.mUrl = uri.toString();
-
-        if (state.mUrl.equals(UrlConstants.BOOKMARKS_URL)) {
-            state.mState = STATE_ALL_BOOKMARKS;
-        } else if (state.mUrl.startsWith(UrlConstants.BOOKMARKS_FOLDER_URL)) {
-            String path = uri.getLastPathSegment();
+        if (url.equals(UrlConstants.BOOKMARKS_URL)) {
+            return createAllBookmarksState(bookmarkModel);
+        } else if (url.startsWith(UrlConstants.BOOKMARKS_FOLDER_URL)) {
+            String path = url.substring(UrlConstants.BOOKMARKS_FOLDER_URL.length());
             if (!path.isEmpty()) {
-                state.mFolder = BookmarkId.getBookmarkIdFromString(path);
-                state.mState = STATE_FOLDER;
+                BookmarkId folder = BookmarkId.getBookmarkIdFromString(path);
+                return createFolderState(folder, bookmarkModel);
             }
         }
-
-        if (!state.isValid(bookmarkModel)) {
-            state.mState = STATE_ALL_BOOKMARKS;
-            state.mUrl = UrlConstants.BOOKMARKS_URL;
-        }
-
-        return state;
+        // If this line is reached, the url is not valid. Fall back to all bookmarks.
+        return createAllBookmarksState(bookmarkModel);
     }
 
+    @VisibleForTesting
     static Uri createFolderUrl(BookmarkId folderId) {
         Uri.Builder builder = Uri.parse(UrlConstants.BOOKMARKS_FOLDER_URL).buildUpon();
-        // Encodes the path and appends it to the base url. A simple appending
-        // does not work because there might be spaces in suffix.
         builder.appendPath(folderId.toString());
         return builder.build();
     }
@@ -100,18 +95,4 @@ class BookmarkUIState {
         BookmarkUIState other = (BookmarkUIState) obj;
         return mState == other.mState && TextUtils.equals(mUrl, other.mUrl);
     }
-
-    /**
-     * @return Whether this state is valid.
-     */
-    boolean isValid(BookmarkModel bookmarkModel) {
-        if (mUrl == null || mState == STATE_INVALID) return false;
-
-        if (mState == STATE_FOLDER) {
-            return mFolder != null && bookmarkModel.doesBookmarkExist(mFolder)
-                    && !mFolder.equals(bookmarkModel.getRootFolderId());
-        }
-
-        return true;
-    }
 }