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

ios/chrome/browser/find_in_page/find_in_page_controller.mm

Index: ios/chrome/browser/find_in_page/find_in_page_controller.mm
diff --git a/ios/chrome/browser/find_in_page/find_in_page_controller.mm b/ios/chrome/browser/find_in_page/find_in_page_controller.mm
index 5a7b6cf833f7c54877ba0f5b3495a17ac87fb15a..1f167a0f4d17356a9da6522ab8a007747ff04151 100644
--- a/ios/chrome/browser/find_in_page/find_in_page_controller.mm
+++ b/ios/chrome/browser/find_in_page/find_in_page_controller.mm
@@ -5,13 +5,14 @@
 #import "ios/chrome/browser/find_in_page/find_in_page_controller.h"
 
 #import <UIKit/UIKit.h>
+
 #import <cmath>
+#include <memory>
 
 #include "base/ios/ios_util.h"
 #include "base/logging.h"
 #include "base/mac/foundation_util.h"
 #include "base/mac/scoped_nsobject.h"
-#include "base/memory/scoped_ptr.h"
 #import "ios/chrome/browser/find_in_page/find_in_page_model.h"
 #import "ios/chrome/browser/find_in_page/js_findinpage_manager.h"
 #import "ios/chrome/browser/web/dom_altering_lock.h"
@@ -81,7 +82,7 @@ const NSTimeInterval kRecurringPumpDelay = .01;
   BOOL _findStringStarted;
 
   // Bridge to observe the web state from Objective-C.
-  scoped_ptr<web::WebStateObserverBridge> _webStateObserverBridge;
+  std::unique_ptr<web::WebStateObserverBridge> _webStateObserverBridge;
 }
 
 @synthesize delegate = _delegate;