Implement location arbitration (kudos to previous internal projects this is lifted from)

BUG=38509
TEST=GeolocationLocationArbitratorTest.Arbitration

Review URL: http://codereview.chromium.org/2376001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@48631 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 39 insertions, 4 deletions

diff --git a/chrome/browser/geolocation/location_arbitrator.h b/chrome/browser/geolocation/location_arbitrator.h
index 4742e56..085e320 100644
--- a/chrome/browser/geolocation/location_arbitrator.h
+++ b/chrome/browser/geolocation/location_arbitrator.h
@@ -5,6 +5,8 @@
 #ifndef CHROME_BROWSER_GEOLOCATION_LOCATION_ARBITRATOR_H_
 #define CHROME_BROWSER_GEOLOCATION_LOCATION_ARBITRATOR_H_
 
+#include "base/string16.h"
+#include "base/time.h"
 #include "base/ref_counted.h"
 
 class AccessTokenStore;
@@ -23,11 +25,37 @@ struct Geoposition;
 // moment.
 class GeolocationArbitrator : public base::RefCounted<GeolocationArbitrator> {
  public:
+  // Number of milliseconds newer a location provider has to be that it's worth
+  // switching to this location provider on the basis of it being fresher
+  // (regardles of relative accuracy). Public for tests.
+  static const int64 kFixStaleTimeoutMilliseconds;
+
+  // Defines a function that returns the current time.
+  typedef base::Time (*GetTimeNow)();
+
+  // Allows injection of factory methods for creating the location providers.
+  // RefCounted for simplicity of writing tests.
+  class ProviderFactory  : public base::RefCounted<ProviderFactory> {
+   public:
+    virtual LocationProviderBase* NewNetworkLocationProvider(
+        AccessTokenStore* access_token_store,
+        URLRequestContextGetter* context,
+        const GURL& url,
+        const string16& access_token) = 0;
+    virtual LocationProviderBase* NewGpsLocationProvider() = 0;
+
+   protected:
+    friend class base::RefCounted<ProviderFactory>;
+    virtual ~ProviderFactory();
+  };
+
   // Creates and returns a new instance of the location arbitrator. Allows
-  // injection of the access token store and url getter context, for testing.
+  // injection of dependencies, for testing.
   static GeolocationArbitrator* Create(
       AccessTokenStore* access_token_store,
-      URLRequestContextGetter* context_getter);
+      URLRequestContextGetter* context_getter,
+      GetTimeNow get_time_now,
+      ProviderFactory* provider_factory);
 
   // Gets a pointer to the singleton instance of the location arbitrator, which
   // is in turn bound to the browser's global context objects. Ownership is NOT
@@ -55,7 +83,7 @@ class GeolocationArbitrator : public base::RefCounted<GeolocationArbitrator> {
   // The update options passed are used as a 'hint' for the provider preferences
   // for this particular observer, however the delegate could receive callbacks
   // for best available locations from any active provider whilst it is
-  // registerd.
+  // registered.
   // If an existing delegate is added a second time it's options are updated
   // but only a single call to RemoveObserver() is required to remove it.
   virtual void AddObserver(Delegate* delegate,
@@ -64,6 +92,11 @@ class GeolocationArbitrator : public base::RefCounted<GeolocationArbitrator> {
   // via AddObserver(). Returns true if the observer was removed.
   virtual bool RemoveObserver(Delegate* delegate) = 0;
 
+  // Returns the current position estimate, or an uninitialized position
+  // if none is yet available. Once initialized, this will always match
+  // the most recent observer notification (via Delegate::OnLocationUpdate()).
+  virtual Geoposition GetCurrentPosition() = 0;
+
   // Called everytime permission is granted to a page for using geolocation.
   // This may either be through explicit user action (e.g. responding to the
   // infobar prompt) or inferred from a persisted site permission.
@@ -75,8 +108,10 @@ class GeolocationArbitrator : public base::RefCounted<GeolocationArbitrator> {
   // OnPermissionGranted().
   virtual bool HasPermissionBeenGranted() const = 0;
 
-  // For testing, a factory functino can be set which will be used to create
+  // For testing, a factory function can be set which will be used to create
   // a specified test provider. Pass NULL to reset to the default behavior.
+  // For finer grained control, use class ProviderFactory instead.
+  // TODO(joth): Move all tests to use ProviderFactory and remove this.
   typedef LocationProviderBase* (*LocationProviderFactoryFunction)(void);
   static void SetProviderFactoryForTest(
       LocationProviderFactoryFunction factory_function);