Disable drag-and-drop for StartSurface for now

Bug: 1005931
Change-Id: If6e7f76d463ded6e30468bcaddd3bc99e3f94b13
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1825902Reviewed-by: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Commit-Queue: Yue Zhang <yuezhanggg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#700034}

chrome/android/features/tab_ui/java/src/org/chromium/chrome/browser/tasks/tab_management/TabGridItemTouchHelperCallback.java

@@ -83,9 +83,13 @@ public class TabGridItemTouchHelperCallback extends ItemTouchHelper.SimpleCallba
         boolean isTabGroupEnabled = FeatureUtilities.isTabGroupsAndroidEnabled();
         boolean isTabGroupUiImprovementEnabled =
                 FeatureUtilities.isTabGroupsAndroidUiImprovementsEnabled();
+        boolean isStartSurfaceEnabled = FeatureUtilities.isStartSurfaceEnabled();
         // Only enable drag for users with group disabled, or with group and group ui improvement
-        // enabled at the same time.
-        boolean isDragEnabled = !isTabGroupEnabled || isTabGroupUiImprovementEnabled;
+        // enabled at the same time. Also, disable drag for start surface for now.
+        // TODO(crbug.com/1005931): Figure out how drag-to-reorder lives in StartSurface MRU
+        // ordering scenario.
+        boolean isDragEnabled =
+                !isStartSurfaceEnabled && (!isTabGroupEnabled || isTabGroupUiImprovementEnabled);
         mDragFlags = isDragEnabled ? ItemTouchHelper.START | ItemTouchHelper.END
                         | ItemTouchHelper.UP | ItemTouchHelper.DOWN
                                    : 0;

chrome/android/features/tab_ui/java/src/org/chromium/chrome/browser/tasks/tab_management/TabSwitcherCoordinator.java

@@ -127,7 +127,8 @@ public class TabSwitcherCoordinator implements Destroyable, TabSwitcher,
                 mTabListCoordinator.getContainerView(), TabListContainerViewBinder::bind);
 
         if (FeatureUtilities.isTabGroupsAndroidUiImprovementsEnabled()
-                && mode == TabListCoordinator.TabListMode.GRID) {
+                && mode == TabListCoordinator.TabListMode.GRID
+                && !FeatureUtilities.isStartSurfaceEnabled()) {
             mTabGridIphItemCoordinator = new TabGridIphItemCoordinator(
                     context, mTabListCoordinator.getContainerView(), container);
             mMediator.setIphProvider(mTabGridIphItemCoordinator.getIphProvider());