[Android] Enhanced bookmark default mobile folder experiment.

chrome/android/java/src/org/chromium/chrome/browser/enhancedbookmarks/EnhancedBookmarkManager.java

Index: chrome/android/java/src/org/chromium/chrome/browser/enhancedbookmarks/EnhancedBookmarkManager.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/enhancedbookmarks/EnhancedBookmarkManager.java b/chrome/android/java/src/org/chromium/chrome/browser/enhancedbookmarks/EnhancedBookmarkManager.java
index f8e161139336c1c0a1081fd17bf22560244c5967..bb36d37553390673fa0f0d4a80c922b87fb4e1d6 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/enhancedbookmarks/EnhancedBookmarkManager.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/enhancedbookmarks/EnhancedBookmarkManager.java
@@ -31,6 +31,7 @@ import org.chromium.chrome.browser.profiles.Profile;
 import org.chromium.chrome.browser.snackbar.SnackbarManager;
 import org.chromium.chrome.browser.snackbar.SnackbarManager.SnackbarManageable;
 import org.chromium.components.bookmarks.BookmarkId;
+import org.chromium.components.variations.VariationsAssociatedData;
 
 import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
@@ -49,6 +50,8 @@ import java.util.Stack;
 public class EnhancedBookmarkManager implements EnhancedBookmarkDelegate {
     private static final String PREF_LAST_USED_URL = "enhanced_bookmark_last_used_url";
     private static final int FAVICON_MAX_CACHE_SIZE_BYTES = 10 * 1024 * 1024; // 10MB
+    private static final String FIELD_TRIAL_NAME = "EnhancedBookmarks";
+    private static final String DEFAULT_FOLDER = "default_folder";
 
     private Activity mActivity;
     private ViewGroup mMainView;
@@ -542,7 +545,14 @@ public class EnhancedBookmarkManager implements EnhancedBookmarkDelegate {
             state.mUrl = url;
 
             if (url.equals(UrlConstants.BOOKMARKS_URL)) {
-                state.mState = STATE_ALL_BOOKMARKS;
+                if (VariationsAssociatedData
+                        .getVariationParamValue(FIELD_TRIAL_NAME, DEFAULT_FOLDER)
+                        .equals("mobile")) {
+                    state.mFolder = bookmarkModel.getMobileFolderId();
+                    state.mState = STATE_FOLDER;
+                } else {
+                    state.mState = STATE_ALL_BOOKMARKS;
+                }
             } else if (url.startsWith(UrlConstants.BOOKMARKS_FOLDER_URL)) {
                 String suffix = decodeSuffix(url, UrlConstants.BOOKMARKS_FOLDER_URL);
                 if (!suffix.isEmpty()) {