Remove remaining calls to deprecated MessageLoop methods.

mojo/public/cpp/bindings/tests/validation_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <algorithm>
 #include <string>
 #include <utility>
@@ skipping 236 matching lines @@
 
     bool Accept(Message* message) override {
       return connector_.Accept(message);
     }
 
    public:
     ValidationIntegrationTest* owner_;
     mojo::Connector connector_;
   };
 
-  void PumpMessages() { loop_.RunUntilIdle(); }
+  void PumpMessages() { base::RunLoop().RunUntilIdle(); }
 
   TestMessageReceiver* test_message_receiver_;
   ScopedMessagePipeHandle testee_endpoint_;
 };
 
 class IntegrationTestInterfaceImpl : public IntegrationTestInterface {
  public:
   ~IntegrationTestInterfaceImpl() override {}
 
   void Method0(BasicStructPtr param0,
@@ skipping 222 matching lines @@
   EXPECT_TRUE(IsKnownEnumValue(static_cast<StructWithEnum::EnumWithin>(0)));
   EXPECT_TRUE(IsKnownEnumValue(static_cast<StructWithEnum::EnumWithin>(1)));
   EXPECT_TRUE(IsKnownEnumValue(static_cast<StructWithEnum::EnumWithin>(2)));
   EXPECT_TRUE(IsKnownEnumValue(static_cast<StructWithEnum::EnumWithin>(3)));
   EXPECT_FALSE(IsKnownEnumValue(static_cast<StructWithEnum::EnumWithin>(4)));
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace mojo