[ObjC ARC] Converts components/translate/ios/browser:browser to ARC.

components/translate/ios/browser/js_translate_manager.mm

Index: components/translate/ios/browser/js_translate_manager.mm
diff --git a/components/translate/ios/browser/js_translate_manager.mm b/components/translate/ios/browser/js_translate_manager.mm
index 47f2a4e3e0c21cbb365b312a2fc86efcf8fcadd9..018666fb7fe7c20bc81f17b0be1f71ea662af308 100644
--- a/components/translate/ios/browser/js_translate_manager.mm
+++ b/components/translate/ios/browser/js_translate_manager.mm
@@ -10,14 +10,17 @@
 
 #include "base/logging.h"
 #include "base/mac/bundle_locations.h"
-#import "base/mac/scoped_nsobject.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
 
 @implementation JsTranslateManager {
-  base::scoped_nsobject<NSString> _translationScript;
+  NSString* _translationScript;
 }
 
 - (NSString*)script {
-  return _translationScript.get();
+  return _translationScript;
 }
 
 - (void)setScript:(NSString*)script {
@@ -43,7 +46,7 @@
                                                    error:&error];
   DCHECK(!error && [content length]);
   script = [script stringByAppendingString:content];
-  _translationScript.reset([script copy]);
+  _translationScript = [script copy];
 }
 
 - (void)injectWaitUntilTranslateReadyScript {
@@ -75,7 +78,9 @@
 
 - (NSString*)injectionContent {
   DCHECK(_translationScript);
-  return _translationScript.autorelease();
+  NSString* translationScript = _translationScript;
+  _translationScript = nil;
+  return translationScript;
 }
 
 @end