Upstream PO2TS_IOS unit test.

components/signin/core/browser/test_signin_client.cc

Index: components/signin/core/browser/test_signin_client.cc
diff --git a/components/signin/core/browser/test_signin_client.cc b/components/signin/core/browser/test_signin_client.cc
index af05dd1ec05c9c96a1850a060cad0a6d23408da5..e197354138296c3d65d786b483a033536afd3728 100644
--- a/components/signin/core/browser/test_signin_client.cc
+++ b/components/signin/core/browser/test_signin_client.cc
@@ -9,6 +9,10 @@
 #include "components/webdata/common/web_database_service.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if defined(OS_IOS)
+#include "ios/public/test/fake_profile_oauth2_token_service_ios_provider.h"
+#endif
+
 TestSigninClient::TestSigninClient()
     : request_context_(new net::TestURLRequestContextGetter(
           base::MessageLoopProxy::current())) {
@@ -56,8 +60,14 @@ void TestSigninClient::SetCookieChangedCallback(
 
 #if defined(OS_IOS)
 ios::ProfileOAuth2TokenServiceIOSProvider* TestSigninClient::GetIOSProvider() {
-  // Just returns NULL for now. It should be changed to return an
-  // |ios::FakeProfileOAuth2TokenServiceIOSProvider|.
-  return NULL;
+  return GetIOSProviderAsFake();
+}
+
+ios::FakeProfileOAuth2TokenServiceIOSProvider*
+TestSigninClient::GetIOSProviderAsFake() {
+  if (!iosProvider_) {
+    iosProvider_.reset(new ios::FakeProfileOAuth2TokenServiceIOSProvider());
+  }
+  return iosProvider_.get();
 }
 #endif