Convert //ios from scoped_ptr to std::unique_ptr.

ios/chrome/test/ios_chrome_unit_test_suite.mm

Index: ios/chrome/test/ios_chrome_unit_test_suite.mm
diff --git a/ios/chrome/test/ios_chrome_unit_test_suite.mm b/ios/chrome/test/ios_chrome_unit_test_suite.mm
index 203d2f233f6f64c2102fd79c6827209f63358898..f72ea03e897253ecdf61bf8d8263e8a8752351d1 100644
--- a/ios/chrome/test/ios_chrome_unit_test_suite.mm
+++ b/ios/chrome/test/ios_chrome_unit_test_suite.mm
@@ -51,10 +51,10 @@ class IOSChromeUnitTestSuiteInitializer
   }
 
  private:
-  scoped_ptr<web::WebClient> web_client_;
-  scoped_ptr<ios::TestChromeProviderInitializer>
+  std::unique_ptr<web::WebClient> web_client_;
+  std::unique_ptr<ios::TestChromeProviderInitializer>
       test_ios_chrome_provider_initializer_;
-  scoped_ptr<ApplicationContext> application_context_;
+  std::unique_ptr<ApplicationContext> application_context_;
   DISALLOW_COPY_AND_ASSIGN(IOSChromeUnitTestSuiteInitializer);
 };