Return unique_ptr from WebClient::CreateWebMainParts()

ios/web/public/web_client.h

Index: ios/web/public/web_client.h
diff --git a/ios/web/public/web_client.h b/ios/web/public/web_client.h
index a852a760058eaaa86d52960f3a24185b4aca0fb7..ffad5f88a7f6cda56eaacfed69ced0e63a6d95d4 100644
--- a/ios/web/public/web_client.h
+++ b/ios/web/public/web_client.h
@@ -5,6 +5,7 @@
 #ifndef IOS_WEB_PUBLIC_WEB_CLIENT_H_
 #define IOS_WEB_PUBLIC_WEB_CLIENT_H_
 
+#include <memory>
 #include <string>
 #include <vector>
 
@@ -50,7 +51,7 @@ class WebClient {
 
   // Allows the embedder to set a custom WebMainParts implementation for the
   // browser startup code.
-  virtual WebMainParts* CreateWebMainParts();
+  virtual std::unique_ptr<WebMainParts> CreateWebMainParts();
 
   // Gives the embedder a chance to perform tasks before a web view is created.
   virtual void PreWebViewCreation() const {}