[MD Bookmarks] Right click on bookmark items open context menu.

chrome/test/data/webui/md_bookmarks/item_test.js

Index: chrome/test/data/webui/md_bookmarks/item_test.js
diff --git a/chrome/test/data/webui/md_bookmarks/item_test.js b/chrome/test/data/webui/md_bookmarks/item_test.js
index 5b39c7d67774c1d5e438b645eb7d49dbc2ddb5ff..4d29419044d668050da7898479740a369c90ae50 100644
--- a/chrome/test/data/webui/md_bookmarks/item_test.js
+++ b/chrome/test/data/webui/md_bookmarks/item_test.js
@@ -48,4 +48,16 @@ suite('<bookmarks-item>', function() {
         bookmarks.actions.selectItem('2', false, false, store.data),
         store.lastAction);
   });
+
+  test('context menu selects item if unselected', function() {
+    item.isSelectedItem_ = true;
+    item.dispatchEvent(new MouseEvent('contextmenu'));
+    assertEquals(null, store.lastAction);
+
+    item.isSelectedItem_ = false;
+    item.dispatchEvent(new MouseEvent('contextmenu'));
+    assertDeepEquals(
+        bookmarks.actions.selectItem('2', false, false, store.data),
+        store.lastAction);
+  });
 });