From bfcb04c19681f117df06151cdc4f3f3343f83676 Mon Sep 17 00:00:00 2001
From: Eric Anderson <ejona@google.com>
Date: Mon, 11 Jul 2016 10:02:23 -0700
Subject: [PATCH] core: Allow avoiding Provider loading, for Android

---
 .../grpc/internal/AbstractManagedChannelImplBuilder.java | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/core/src/main/java/io/grpc/internal/AbstractManagedChannelImplBuilder.java b/core/src/main/java/io/grpc/internal/AbstractManagedChannelImplBuilder.java
index 9f18adfb6d..c514553389 100644
--- a/core/src/main/java/io/grpc/internal/AbstractManagedChannelImplBuilder.java
+++ b/core/src/main/java/io/grpc/internal/AbstractManagedChannelImplBuilder.java
@@ -241,11 +241,18 @@ public abstract class AbstractManagedChannelImplBuilder
       transportFactory = new AuthorityOverridingTransportFactory(
         transportFactory, authorityOverride);
     }
+    NameResolver.Factory nameResolverFactory = this.nameResolverFactory;
+    if (nameResolverFactory == null) {
+      // Avoid loading the provider unless necessary, as a way to workaround a possibly-costly
+      // and poorly optimized getResource() call on Android. If any other piece of code calls
+      // getResource(), then this shouldn't be a problem unless called on the UI thread.
+      nameResolverFactory = NameResolverProvider.asFactory();
+    }
     return new ManagedChannelImpl(
         target,
         // TODO(carl-mastrangelo): Allow clients to pass this in
         new ExponentialBackoffPolicy.Provider(),
-        firstNonNull(nameResolverFactory, NameResolverProvider.asFactory()),
+        nameResolverFactory,
         getNameResolverParams(),
         firstNonNull(loadBalancerFactory, DummyLoadBalancerFactory.getInstance()),
         transportFactory,