sensors: Remove SensorProviderProxy::sensor_proxies().

This method is not used anywhere, including SensorProviderProxy's
friends, so get rid of it for simplicity's sake.

Change-Id: Ibf9484f935372d733ab4d4dda991cb53c6cfeb4d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2421368
Auto-Submit: Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
Commit-Queue: Reilly Grant <reillyg@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809679}

third_party/blink/renderer/modules/sensor/sensor_provider_proxy.h

@@ -48,15 +48,13 @@ class MODULES_EXPORT SensorProviderProxy final
     return sensor_provider_.get();
   }
   void RemoveSensorProxy(SensorProxy* proxy);
-  using SensorsSet = HeapHashSet<WeakMember<SensorProxy>>;
-  const SensorsSet& sensor_proxies() const { return sensor_proxies_; }
 
   // For SensorProviderProxy personal use.
   void InitializeIfNeeded();
   bool IsInitialized() const { return sensor_provider_.is_bound(); }
   void OnSensorProviderConnectionError();
-  SensorsSet sensor_proxies_;
 
+  HeapHashSet<WeakMember<SensorProxy>> sensor_proxies_;
   HeapMojoRemote<device::mojom::blink::SensorProvider,
                  HeapMojoWrapperMode::kWithoutContextObserver>
       sensor_provider_;