Hooks together Geolocation Feature in the Client and Engine.

device/geolocation/rate_limiting_location_provider_proxy.h

Index: device/geolocation/rate_limiting_location_provider_proxy.h
diff --git a/device/geolocation/rate_limiting_location_provider_proxy.h b/device/geolocation/rate_limiting_location_provider_proxy.h
new file mode 100644
index 0000000000000000000000000000000000000000..df37c3821edb0aaea3d606ae1a9d6ecbac83d905
--- /dev/null
+++ b/device/geolocation/rate_limiting_location_provider_proxy.h
@@ -0,0 +1,49 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef DEVICE_GEOLOCATION_RATE_LIMITING_LOCATION_PROVIDER_PROXY_H_
+#define DEVICE_GEOLOCATION_RATE_LIMITING_LOCATION_PROVIDER_PROXY_H_
+
+#include <memory>
+
+#include "device/geolocation/geolocation_delegate.h"
+#include "device/geolocation/geoposition.h"
+#include "device/geolocation/location_provider.h"
+
+namespace device {
+
+// Location provider that limits the rate of geolocation updates.
+// TODO(lethalantidote): Schedule aspect still to be implemented. Dummy for now.

[Wez, 2016/08/24 23:07:18]

What is the point of having a "dummy" that doesn't implement the actual
functionality?

[CJ, 2016/08/25 19:08:22]

I can make a baseline to see if the techniques I proposed actually work. I can
also see if functionality is the same between blimp and normal geolocation
without rate limiting before I apply things. Also smaller CL. 

[Wez, 2016/08/30 00:03:58]

Right, but you don't need the RateLimitingLocationProviderProxy for a baseline -
you can just pass the LocationArbitrator directly to the GeolocationProviderImpl
to use, rather than passing the rate-limiter.

It would be reasonable to rename this to LocationProviderProxy and keep it to
use as a base-class for RateLimitingLocationProvider, but that could still
happen in a separate CL - this do-nothing proxy doesn't seem to be relevant to
hooking the GeolocationFeature up in the client.

[CJ, 2016/08/31 23:22:56]

Done.

+class DEVICE_GEOLOCATION_EXPORT RateLimitingLocationProviderProxy
+    : public LocationProvider {
+ public:
+  RateLimitingLocationProviderProxy();
+  ~RateLimitingLocationProviderProxy() override;
+
+  void SetLocationProviderForTest(
+      std::unique_ptr<LocationProvider> location_provider);

[Wez, 2016/08/24 23:07:18]

If this is only for test then how does a caller provide the underlying
LocationProvider they want to use in production code?

[CJ, 2016/08/25 19:08:22]

Good point, its gone, constructor now handles it.

+
+  // LocationProvider implemenation.
+  void SetUpdateCallback(
+      const LocationProviderUpdateCallback& callback) override;
+  bool StartProvider(bool enable_high_accuracy) override;
+  void StopProvider() override;
+  const Geoposition& GetPosition() override;
+  void OnPermissionGranted() override;
+
+ private:
+  // Limits the rate in which location updates from |location_provider_| will

[Wez, 2016/08/24 23:07:18]

nit: s/in/at

[CJ, 2016/08/25 19:08:22]

Done.

+  // get passed along through |feature_update_callback_|.
+  void OnLocationUpdate(const LocationProvider* provider,
+                        const Geoposition& new_position);
+
+  std::unique_ptr<LocationProvider> location_provider_;
+  LocationProvider::LocationProviderUpdateCallback feature_update_callback_;

[Wez, 2016/08/24 23:07:18]

What is "feature" in this context?

[CJ, 2016/08/25 19:08:22]

Good point. 

+
+  DISALLOW_COPY_AND_ASSIGN(RateLimitingLocationProviderProxy);
+};
+
+}  // namespace device
+
+#endif  // DEVICE_GEOLOCATION_RATE_LIMITING_LOCATION_PROVIDER_PROXY_H_