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 873a63040e376498f5b8f36830d86890a3c2776b..3c924cd9fe1583fcc5195da8573311a169feec00 100644
--- a/ash/mus/shell_delegate_mus.cc
+++ b/ash/mus/shell_delegate_mus.cc
@@ -113,6 +113,10 @@ class ShelfDelegateStub : public ShelfDelegate {
   void OnShelfAutoHideStateChanged(WmShelf* shelf) override {}
   void OnShelfVisibilityStateChanged(WmShelf* shelf) override {}
   ShelfID GetShelfIDForAppID(const std::string& app_id) override { return 0; }
+  ShelfID GetShelfIDForAppIDAndLaunchID(const std::string& app_id,
+                                        const std::string& launch_id) override {
+    return 0;
+  }
   bool HasShelfIDToAppIDMapping(ShelfID id) const override { return false; }
   const std::string& GetAppIDForShelfID(ShelfID id) override {
     return base::EmptyString();