[iOS] Automatic UA is restored when flag is enabled

This CL makes sure that the AUTOMATIC UserAgentType is restored in the
WebState when the flag to have the AUTOMATIC UserAgent is enabled.
In some cases (for example after updating the flag), the session is
restored with the AUTOMATIC UserAgent, leading to a DCHECK.

Bug: None
Change-Id: Iceb9e8b2af25db987e80f07e9fbb2911d0c4f0c6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2329709Reviewed-by: Ali Juma <ajuma@chromium.org>
Reviewed-by: Sebastien Lalancette <seblalancette@chromium.org>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Auto-Submit: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#793604}

ios/web/navigation/session_storage_builder.mm

@@ -8,6 +8,7 @@
 
 #include "base/check_op.h"
 #include "base/mac/foundation_util.h"
+#include "ios/web/common/features.h"
 #import "ios/web/navigation/navigation_item_impl.h"
 #import "ios/web/navigation/navigation_item_storage_builder.h"
 #include "ios/web/navigation/navigation_manager_impl.h"
@@ -113,7 +114,12 @@ void SessionStorageBuilder::ExtractSessionState(
   web_state->certificate_policy_cache_ = std::move(cert_policy_cache);
   web::SerializableUserDataManager::FromWebState(web_state)
       ->AddSerializableUserData(storage.userData);
-  web_state->SetUserAgent(storage.userAgentType);
+  UserAgentType user_agent_type = storage.userAgentType;
+  if (user_agent_type == UserAgentType::AUTOMATIC &&
+      !features::UseWebClientDefaultUserAgent()) {
+    user_agent_type = UserAgentType::MOBILE;
+  }
+  web_state->SetUserAgent(user_agent_type);
 }
 
 }  // namespace web

ios/web/session/crw_session_storage.mm

@@ -110,8 +110,13 @@ NSString* const kLastCommittedItemIndexDeprecatedKey =
                forKey:kCertificatePolicyCacheStorageKey];
   if (_userData)
     _userData->Encode(coder);
+  web::UserAgentType userAgentType = _userAgentType;
+  if (userAgentType == web::UserAgentType::AUTOMATIC &&
+      !web::features::UseWebClientDefaultUserAgent()) {
+    userAgentType = web::UserAgentType::MOBILE;
+  }
   web::nscoder_util::EncodeString(
-      coder, kUserAgentKey, web::GetUserAgentTypeDescription(_userAgentType));
+      coder, kUserAgentKey, web::GetUserAgentTypeDescription(userAgentType));
 }
 
 @end