Enhance chrome.app.window API for shelf integration with pinning support

ash/mus/shelf_delegate_mus.cc

Index: ash/mus/shelf_delegate_mus.cc
diff --git a/ash/mus/shelf_delegate_mus.cc b/ash/mus/shelf_delegate_mus.cc
index 3f6292bb387fb7f3d51406b5e20c4e2a61716412..fdb2bdeaf0076d25c14ae1395c6344cc5a2102f7 100644
--- a/ash/mus/shelf_delegate_mus.cc
+++ b/ash/mus/shelf_delegate_mus.cc
@@ -201,6 +201,12 @@ ShelfID ShelfDelegateMus::GetShelfIDForAppID(const std::string& app_id) {
   return 0;
 }
 
+ShelfID ShelfDelegateMus::GetShelfIDForAppIDAndLaunchID(
+    const std::string& app_id,
+    const std::string& launch_id) {
+  return ShelfDelegateMus::GetShelfIDForAppID(app_id);
+}
+
 bool ShelfDelegateMus::HasShelfIDToAppIDMapping(ShelfID id) const {
   return shelf_id_to_app_id_.count(id) != 0;
 }