[Sync] Fix namespaces for the sync_sessions component.

components/sync_sessions/revisit/sessions_page_revisit_observer_unittest.cc

 // Copyright 2015 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 "components/sync_sessions/revisit/sessions_page_revisit_observer.h"
 
 #include <memory>
 #include <string>
 
 #include "base/memory/ptr_util.h"
 #include "base/test/histogram_tester.h"
 #include "components/sessions/core/serialized_navigation_entry.h"
 #include "components/sessions/core/serialized_navigation_entry_test_helper.h"
 #include "components/sessions/core/session_types.h"
 #include "components/sync_sessions/revisit/page_visit_observer.h"
 #include "components/sync_sessions/synced_session.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
 using sessions::SessionTab;
 using sessions::SessionWindow;
-using sync_driver::SyncedSession;
 
 namespace sync_sessions {
 
 namespace {
 
-static const std::string kExampleUrl = "http://www.example.com";
-static const std::string kDifferentUrl = "http://www.different.com";
+static const char kExampleUrl[] = "http://www.example.com";
+static const char kDifferentUrl[] = "http://www.different.com";
 
 class TestForeignSessionsProvider : public ForeignSessionsProvider {
  public:
   TestForeignSessionsProvider(const std::vector<const SyncedSession*>& sessions,
                               bool return_value)
       : sessions_(sessions), return_value_(return_value) {}
   ~TestForeignSessionsProvider() override{};
 
   bool GetAllForeignSessions(
       std::vector<const SyncedSession*>* sessions) override {
@@ skipping 149 matching lines @@
   sessions.push_back(session1.get());
   sessions.push_back(session2.get());
   SessionsPageRevisitObserver observer(
       base::MakeUnique<TestForeignSessionsProvider>(sessions, true));
 
   base::HistogramTester histogram_tester;
   CheckAndExpect(&observer, GURL(kExampleUrl), true, true);
 }
 
 }  // namespace sync_sessions