Make NQE a derived class of NetworkQualityProvider

components/offline_pages/core/background/network_quality_provider_stub.cc

Index: components/offline_pages/core/background/network_quality_provider_stub.cc
diff --git a/components/offline_pages/core/background/network_quality_provider_stub.cc b/components/offline_pages/core/background/network_quality_provider_stub.cc
index 9c5cf28f00f5b244ff4514a371e119739efe4c40..168d277e09a7ef95cfcc408d1a468a25f0bd6a5b 100644
--- a/components/offline_pages/core/background/network_quality_provider_stub.cc
+++ b/components/offline_pages/core/background/network_quality_provider_stub.cc
@@ -30,20 +30,6 @@ void NetworkQualityProviderStub::SetUserData(
   supports_user_data->SetUserData(&kOfflineNQPKey, std::move(stub));
 }
 
-void NetworkQualityProviderStub::AddEffectiveConnectionTypeObserver(
-    net::NetworkQualityEstimator::EffectiveConnectionTypeObserver* observer) {}
-
-void NetworkQualityProviderStub::RemoveEffectiveConnectionTypeObserver(
-    net::NetworkQualityEstimator::EffectiveConnectionTypeObserver* observer) {}
-
-void NetworkQualityProviderStub::AddRTTAndThroughputEstimatesObserver(
-    net::NetworkQualityEstimator::RTTAndThroughputEstimatesObserver* observer) {
-}
-
-void NetworkQualityProviderStub::RemoveRTTAndThroughputEstimatesObserver(
-    net::NetworkQualityEstimator::RTTAndThroughputEstimatesObserver* observer) {
-}
-
 net::EffectiveConnectionType
 NetworkQualityProviderStub::GetEffectiveConnectionType() const {
   return connection_type_;