[Android History] Add accessibility support

chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadManagerToolbar.java

Index: chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadManagerToolbar.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadManagerToolbar.java b/chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadManagerToolbar.java
index 0ebad5c01f240cd9d29e58e7dbad284c77f2ac7e..1e0080232698786a03e41b8bc2ecebc1350a17dd 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadManagerToolbar.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadManagerToolbar.java
@@ -8,6 +8,7 @@ import android.content.Context;
 import android.support.annotation.Nullable;
 import android.support.v4.widget.DrawerLayout;
 import android.util.AttributeSet;
+import android.view.View;
 
 import org.chromium.base.metrics.RecordUserAction;
 import org.chromium.chrome.R;
@@ -38,8 +39,6 @@ public class DownloadManagerToolbar extends SelectionToolbar<DownloadHistoryItem
         }
 
         super.initialize(delegate, titleResId, drawerLayout, normalGroupResId, selectedGroupResId);
-
-        mNumberRollView.setContentDescriptionString(R.plurals.accessibility_selected_items);
     }
 
     @Override
@@ -57,12 +56,22 @@ public class DownloadManagerToolbar extends SelectionToolbar<DownloadHistoryItem
             updateTitle();
         } else {
             int numSelected = mSelectionDelegate.getSelectedItems().size();
-            findViewById(R.id.selection_mode_share_menu_id).setContentDescription(
-                    getResources().getQuantityString(R.plurals.accessibility_share_selected_items,
-                            numSelected, numSelected));
-            findViewById(R.id.selection_mode_delete_menu_id).setContentDescription(
-                    getResources().getQuantityString(R.plurals.accessibility_remove_selected_items,
-                            numSelected, numSelected));
+
+            // If the share or delete menu items are shown in the overflow menu instead of as an
+            // action, there may not be views associated with them.
+            View shareButton = findViewById(R.id.selection_mode_share_menu_id);
+            if (shareButton != null) {
+                shareButton.setContentDescription(getResources().getQuantityString(
+                        R.plurals.accessibility_share_selected_items,
+                                numSelected, numSelected));
+            }
+
+            View deleteButton = findViewById(R.id.selection_mode_delete_menu_id);
+            if (deleteButton != null) {
+                deleteButton.setContentDescription(getResources().getQuantityString(
+                        R.plurals.accessibility_remove_selected_items,
+                        numSelected, numSelected));
+            }
 
             if (!wasSelectionEnabled) {
                 RecordUserAction.record("Android.DownloadManager.SelectionEstablished");