Switch SupportsUserData uses to use unique_ptr.

chromecast/browser/android/cast_web_contents_activity.cc

Index: chromecast/browser/android/cast_web_contents_activity.cc
diff --git a/chromecast/browser/android/cast_web_contents_activity.cc b/chromecast/browser/android/cast_web_contents_activity.cc
index f62fc05c26c5bcf134ed9e92a8167869afb4e842..8f314e598f8c11445badb41168027a2bd65d3782 100644
--- a/chromecast/browser/android/cast_web_contents_activity.cc
+++ b/chromecast/browser/android/cast_web_contents_activity.cc
@@ -4,6 +4,7 @@
 
 #include "chromecast/browser/android/cast_web_contents_activity.h"
 
+#include "base/memory/ptr_util.h"
 #include "content/public/browser/web_contents.h"
 #include "jni/CastWebContentsActivity_jni.h"
 
@@ -46,7 +47,8 @@ CastWebContentsActivity* CastWebContentsActivity::Get(
       web_contents->GetUserData(kCastWebContentsActivityKey));
   if (!instance) {
     instance = new CastWebContentsActivity(web_contents);
-    web_contents->SetUserData(kCastWebContentsActivityKey, instance);
+    web_contents->SetUserData(kCastWebContentsActivityKey,
+                              base::WrapUnique(instance));
   }
   return instance;
 }