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

ios/web/public/test/scoped_testing_web_client.h

Index: ios/web/public/test/scoped_testing_web_client.h
diff --git a/ios/web/public/test/scoped_testing_web_client.h b/ios/web/public/test/scoped_testing_web_client.h
index 51f7969f41e5d0560e009d56f162782ff4b946ae..65a221e2570564d335d33f8818ad70b820493983 100644
--- a/ios/web/public/test/scoped_testing_web_client.h
+++ b/ios/web/public/test/scoped_testing_web_client.h
@@ -5,8 +5,9 @@
 #ifndef IOS_WEB_PUBLIC_TEST_SCOPED_TESTING_WEB_CLIENT_H_
 #define IOS_WEB_PUBLIC_TEST_SCOPED_TESTING_WEB_CLIENT_H_
 
+#include <memory>
+
 #include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
 
 namespace web {
 
@@ -15,13 +16,13 @@ class WebClient;
 // Helper class to register a WebClient during unit testing.
 class ScopedTestingWebClient {
  public:
-  explicit ScopedTestingWebClient(scoped_ptr<WebClient> web_client);
+  explicit ScopedTestingWebClient(std::unique_ptr<WebClient> web_client);
   ~ScopedTestingWebClient();
 
   WebClient* Get();
 
  private:
-  scoped_ptr<WebClient> web_client_;
+  std::unique_ptr<WebClient> web_client_;
   WebClient* original_web_client_;
 };