added CTRL+Click and SHIFT+Click handler for context menu, Back and Forward.

ui/base/models/simple_menu_model.cc

Index: ui/base/models/simple_menu_model.cc
diff --git a/ui/base/models/simple_menu_model.cc b/ui/base/models/simple_menu_model.cc
index 57f6ec3e736ce04d06a0a35047a3d8e278916c0e..4adbaece65b61de6b9c1a24107e6c0485e1870bf 100644
--- a/ui/base/models/simple_menu_model.cc
+++ b/ui/base/models/simple_menu_model.cc
@@ -52,6 +52,11 @@ void SimpleMenuModel::Delegate::MenuWillShow() {
 void SimpleMenuModel::Delegate::MenuClosed() {
 }
 
+void SimpleMenuModel::Delegate::ExecuteCommandWithFlags(
+    int command_id, int flags) {
+  ExecuteCommand(command_id);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // SimpleMenuModel, public:
 
@@ -290,6 +295,11 @@ void SimpleMenuModel::ActivatedAt(int index) {
     delegate_->ExecuteCommand(GetCommandIdAt(index));
 }
 
+void SimpleMenuModel::ActivatedAtWithFlags(int index, int flags) {
+  if (delegate_)
+    delegate_->ExecuteCommandWithFlags(GetCommandIdAt(index), flags);
+}
+
 MenuModel* SimpleMenuModel::GetSubmenuModelAt(int index) const {
   return items_.at(FlipIndex(index)).submenu;
 }