Adds GeolocationFeature for Blimp Geolocation project.

blimp/client/feature/geolocation_feature.h

Index: blimp/client/feature/geolocation_feature.h
diff --git a/blimp/client/feature/geolocation_feature.h b/blimp/client/feature/geolocation_feature.h
new file mode 100644
index 0000000000000000000000000000000000000000..77a1c41c4e72473da89898064f7dcd090c47754b
--- /dev/null
+++ b/blimp/client/feature/geolocation_feature.h
@@ -0,0 +1,64 @@
+// 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 BLIMP_CLIENT_FEATURE_GEOLOCATION_FEATURE_H_
+#define BLIMP_CLIENT_FEATURE_GEOLOCATION_FEATURE_H_
+
+#include <memory>
+
+#include "blimp/common/proto/geolocation.pb.h"
+#include "blimp/net/blimp_message_processor.h"
+#include "content/public/common/geoposition.h"
+
+namespace blimp {
+namespace client {
+
+// Handles all incoming and outgoing protobu messages of type

[Kevin M, 2016/07/20 17:30:15]

typo

This is a literal description of how the class behaves, but I think a more
succinct, plain-English description might suffice.

[CJ, 2016/07/20 23:22:10]

Done.

+// Geolocation. A delegate can be added to be notified of incoming messages.
+class GeolocationFeature : public BlimpMessageProcessor {
+ public:
+  // A delegate to be notified of specific geolocation events, such as
+  // change of interest in geolocation updates.
+  class GeolocationFeatureDelegate {
+   public:
+    virtual ~GeolocationFeatureDelegate() {}

[Kevin M, 2016/07/20 17:30:16]

Don't need a virtual dtor if the delegate object isn't owned/deleted here.

[CJ, 2016/07/20 23:22:10]

Done.

+    virtual void OnGeolocationInterestUpdate(

[Kevin M, 2016/07/20 17:30:16]

Document each method and add newlines

[CJ, 2016/07/20 23:22:11]

Done.

+        GeolocationSetInterestLevelMessage::Level level);

[Kevin M, 2016/07/20 17:30:15]

Make these methods pure virtual.

[CJ, 2016/07/20 23:22:10]

Done.

+    virtual void OnRequestRefresh();
+  };
+
+  GeolocationFeature();
+  ~GeolocationFeature() override;
+
+  // Sets the BlimpMessageProcessor that will be used to send
+  // BlimpMessage::GEOLOCATION messages to the engine.
+  void set_outgoing_message_processor(
+      std::unique_ptr<BlimpMessageProcessor> processor);
+
+  // Sets a GeolocationFeatureDelegate to be notified of all geolocation

[Kevin M, 2016/07/20 17:30:16]

"messages" probably not so much... how about "events", or "updates"?

[CJ, 2016/07/20 23:22:11]

Done.

+  // messages from the engine.
+  void SetDelegate(GeolocationFeatureDelegate* delegate);
+
+  void OnLocationUpdate(const content::Geoposition& position);

[Kevin M, 2016/07/20 17:30:15]

Add comment

[CJ, 2016/07/20 23:22:10]

Done.

+
+  // BlimpMessageProcessor implementation.
+  void ProcessMessage(std::unique_ptr<BlimpMessage> message,
+                      const net::CompletionCallback& callback) override;
+
+ private:
+  void SendGeolocationPositionMessage(const content::Geoposition& position);

[Kevin M, 2016/07/20 17:30:15]

Add comment

[CJ, 2016/07/20 23:22:11]

Done.

+  void SendGeolocationErrorMessage(const content::Geoposition& position);

[Kevin M, 2016/07/20 17:30:16]

Add comment

[CJ, 2016/07/20 23:22:10]

Done.

+
+  GeolocationFeatureDelegate* delegate_;

[Kevin M, 2016/07/20 17:30:16]

= nullptr;

[CJ, 2016/07/20 23:22:11]

Done.

+
+  // Used to send BlimpMessage::GEOLOCATION message to the engine.
+  std::unique_ptr<BlimpMessageProcessor> outgoing_message_processor_;
+
+  DISALLOW_COPY_AND_ASSIGN(GeolocationFeature);
+};
+
+}  // namespace client
+}  // namespace blimp
+
+#endif  // BLIMP_CLIENT_FEATURE_GEOLOCATION_FEATURE_H_