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

ash/mus/shell_delegate_mus.cc

Index: ash/mus/shell_delegate_mus.cc
diff --git a/ash/mus/shell_delegate_mus.cc b/ash/mus/shell_delegate_mus.cc
index 285e1a7fc05ba109ee43bf4785d2e51a3d8834ff..da0365e8052d72a12f6b9ce5a216f582b0e16d1f 100644
--- a/ash/mus/shell_delegate_mus.cc
+++ b/ash/mus/shell_delegate_mus.cc
@@ -110,7 +110,10 @@ class ShelfDelegateStub : public ShelfDelegate {
   void OnShelfAutoHideBehaviorChanged(Shelf* shelf) override {}
   void OnShelfAutoHideStateChanged(Shelf* shelf) override {}
   void OnShelfVisibilityStateChanged(Shelf* shelf) override {}
-  ShelfID GetShelfIDForAppID(const std::string& app_id) override { return 0; }
+  ShelfID GetShelfIDForAppID(const std::string& app_id,
+                             const std::string& app_shelf_id) override {
+    return 0;
+  }
   bool HasShelfIDToAppIDMapping(ShelfID id) const override { return false; }
   const std::string& GetAppIDForShelfID(ShelfID id) override {
     return base::EmptyString();