[Android] Add enhanced bookmarks grid/list view experiment.

components/enhanced_bookmarks/enhanced_bookmark_utils.h

 // Copyright 2014 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.
 
 #ifndef COMPONENTS_ENHANCED_BOOKMARKS_ENHANCED_BOOKMARK_UTILS_H_
 #define COMPONENTS_ENHANCED_BOOKMARKS_ENHANCED_BOOKMARK_UTILS_H_
 
 #include <set>
 #include <string>
 #include <vector>
 
 namespace bookmarks {
 class BookmarkModel;
 class BookmarkNode;
 }
 
 namespace enhanced_bookmarks {
 
+extern const char kFieldTrialName[];
+
 // Possible locations where a bookmark can be opened from.
 // Please sync with the corresponding histograms.xml.
 //
 // A Java counterpart will be generated for this enum.
 // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.chrome.browser.enhanced_bookmarks
 enum LaunchLocation {
   ALL_ITEMS = 0,
   UNCATEGORIZED = 1,  // Deprecated.
   FOLDER = 2,
   FILTER = 3,
   SEARCH = 4,
   BOOKMARK_EDITOR = 5,
   COUNT = 6,
 };
 
+// View modes of enhanced bookmarks' main items UI.
+//
+// A Java counterpart will be generated for this enum.
+// GENERATED_JAVA_ENUM_PACKAGE: org.chromium.chrome.browser.enhanced_bookmarks
+enum ViewMode {
+  DEFAULT = 0,
+  LIST = 1,
+  GRID = 2,
+};
+
 // Returns the permanent nodes whose url children are considered uncategorized
 // and whose folder children should be shown in the bookmark menu.
 // |model| must be loaded.
 std::vector<const bookmarks::BookmarkNode*> PrimaryPermanentNodes(
     bookmarks::BookmarkModel* model);
 
 // Returns an unsorted vector of folders that are considered to be at the "root"
 // level of the bookmark hierarchy. Functionally, this means all direct
 // descendants of PrimaryPermanentNodes.
 std::vector<const bookmarks::BookmarkNode*> RootLevelFolders(
     bookmarks::BookmarkModel* model);
 
 // Returns whether |node| is a primary permanent node in the sense of
 // |PrimaryPermanentNodes|.
 bool IsPrimaryPermanentNode(const bookmarks::BookmarkNode* node,
                             bookmarks::BookmarkModel* model);
 
 // Returns the root level folder in which this node is directly, or indirectly
 // via subfolders, located.
 const bookmarks::BookmarkNode* RootLevelFolderForNode(
     const bookmarks::BookmarkNode* node,
     bookmarks::BookmarkModel* model);
 
+// Returns the default view mode for main items UI.
+// It doesn't return ViewMode::DEFAULT.

[Theresa, 2015/05/28 20:13:08]

Can you elaborate with what is returned; e.g. the default is controlled by the
value in the finch experiment.

[Kibeom Kim (inactive), 2015/05/29 00:11:04]

Done.

+ViewMode GetDefaultViewMode();
+
 }  // namespace enhanced_bookmarks
 
 #endif  // COMPONENTS_ENHANCED_BOOKMARKS_ENHANCED_BOOKMARK_UTILS_H_