Geolocation: extract ContentBrowserClient methods specific to Geolocation into a class

content/public/browser/geolocation_provider.h

 // Copyright (c) 2012 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 CONTENT_PUBLIC_BROWSER_GEOLOCATION_PROVIDER_H_
 #define CONTENT_PUBLIC_BROWSER_GEOLOCATION_PROVIDER_H_
 
 #include <memory>
 
 #include "base/callback_list.h"
 #include "content/common/content_export.h"
 
 namespace content {
+class AccessTokenStore;
 struct Geoposition;
+class LocationProvider;
 
 // This is the main API to the geolocation subsystem. The application will hold
 // a single instance of this class and can register multiple clients to be
 // notified of location changes:
 // * Callbacks are registered by AddLocationUpdateCallback() and will keep
 //   receiving updates until the returned subscription object is destructed.
 // The application must instantiate the GeolocationProvider on the UI thread and
 // must communicate with it on the same thread.
 // The underlying location arbitrator will only be enabled whilst there is at
 // least one registered observer or pending callback (and only after
 // UserDidOptIntoLocationServices). The arbitrator and the location providers it
 // uses run on a separate Geolocation thread.
 class GeolocationProvider {
  public:
+  // An Embedder of Geolocation may override these class' methods to provide
+  // specific functionality.
+  class CONTENT_EXPORT ServiceOverrides {

[Michael van Ouwerkerk, 2016/06/24 13:57:19]

I'd suggest calling it GeolocationProvider::Delegate

[mcasas, 2016/06/24 19:25:52]

Done.

+   public:
+    // Returns true if the location API should use network-based location
+    // approximation in addition to the system provider, if any.
+    virtual bool UseNetworkLocationProviders();

[Michael van Ouwerkerk, 2016/06/24 13:57:19]

The first rule of the content API [1] is "content/public should contain only
interfaces, structs and (rarely) static functions" so this should be pure
virtual. When in doubt, ask the content api owners.

[1] https://www.chromium.org/developers/content-module/content-api

[mcasas, 2016/06/24 19:25:53]

I didn't know that rule, but currently there are
52 .cc files in content/public/browser, and some
of them (e.g.  download_manager_delegate.cc) has
class implementation. That said, I'm willing to comply
and will send this CL to content/ OWNERS before 
landing, of course, and we'll see where to put this
file then, SG?

+
+    // Creates a new AccessTokenStore for geolocation. May return nullptr.
+    virtual AccessTokenStore* CreateAccessTokenStore();

[Michael van Ouwerkerk, 2016/06/24 13:57:19]

If you're here anyway, consider whether this should return a unique_ptr for
ownership clarity. You could leave a TODO for doing this as a future change.

[mcasas, 2016/06/24 19:25:52]

Added a TODO and a bug. Smaller CLs are easier
to review :)

+
+    // Allows an embedder to return its own LocationProvider implementation.
+    // Return nullptr to use the default one for the platform to be created.
+    // Caller takes ownership of the returned LocationProvider. FYI: Used by an
+    // external project; please don't remove. Contact Viatcheslav Ostapenko at
+    // sl.ostapenko@samsung.com for more information.
+    virtual LocationProvider* OverrideSystemLocationProvider();
+  };
+
   CONTENT_EXPORT static GeolocationProvider* GetInstance();
 
   typedef base::Callback<void(const Geoposition&)> LocationUpdateCallback;
   typedef base::CallbackList<void(const Geoposition&)>::Subscription
       Subscription;
 
   // |enable_high_accuracy| is used as a 'hint' for the provider preferences for
   // this particular observer, however the observer could receive updates for
   // best available locations from any active provider whilst it is registered.
   virtual std::unique_ptr<Subscription> AddLocationUpdateCallback(
@@ skipping 18 matching lines @@
   // (crbug.com/125931).
   virtual void OverrideLocationForTesting(const Geoposition& position) = 0;
 
  protected:
   virtual~GeolocationProvider() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_GEOLOCATION_PROVIDER_H_