fix: opt into location services once device service has been started (#14253)

* fix: opt into location services once device service has been started

* refactor: provide fake location provider to mock geolocation reponses

* chore: add spec for navigator.geolocation api using fake location provider

atom/browser/fake_location_provider.h

@@ -0,0 +1,36 @@
+// Copyright (c) 2018 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#ifndef ATOM_BROWSER_FAKE_LOCATION_PROVIDER_H_
+#define ATOM_BROWSER_FAKE_LOCATION_PROVIDER_H_
+
+#include "base/macros.h"
+#include "device/geolocation/public/cpp/location_provider.h"
+#include "services/device/public/mojom/geoposition.mojom.h"
+
+namespace atom {
+
+class FakeLocationProvider : public device::LocationProvider {
+ public:
+  FakeLocationProvider();
+  ~FakeLocationProvider() override;
+
+  // LocationProvider Implementation:
+  void SetUpdateCallback(
+      const LocationProviderUpdateCallback& callback) override;
+  void StartProvider(bool high_accuracy) override;
+  void StopProvider() override;
+  const device::mojom::Geoposition& GetPosition() override;
+  void OnPermissionGranted() override;
+
+ private:
+  device::mojom::Geoposition position_;
+  LocationProviderUpdateCallback callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(FakeLocationProvider);
+};
+
+}  // namespace atom
+
+#endif  // ATOM_BROWSER_FAKE_LOCATION_PROVIDER_H_