[PhysicalWeb] Add physical_web namespace.

ios/chrome/test/testing_application_context.mm

 // 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 "ios/chrome/test/testing_application_context.h"
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/time/default_clock.h"
 #include "base/time/default_tick_clock.h"
@@ skipping 137 matching lines @@
 TestingApplicationContext::GetComponentUpdateService() {
   DCHECK(thread_checker_.CalledOnValidThread());
   return nullptr;
 }
 
 CRLSetFetcher* TestingApplicationContext::GetCRLSetFetcher() {
   DCHECK(thread_checker_.CalledOnValidThread());
   return nullptr;
 }
 
-PhysicalWebDataSource* TestingApplicationContext::GetPhysicalWebDataSource() {
+physical_web::PhysicalWebDataSource*
+TestingApplicationContext::GetPhysicalWebDataSource() {
   DCHECK(thread_checker_.CalledOnValidThread());
   return nullptr;
 }