GCC: explicitely std::move to base::Optional instead of implicit conversion to...

GCC: explicitely std::move to base::Optional instead of implicit conversion to base::Optional in return

GCC 7.2/7.3 complains in this pattern of code:
base::Optional<Foo>
Method() {
  ...
  Foo response;
  ...
  return response;
}

It seems it cannot properly resolve the implicit move to base::Optional, and
ends up failing to compile. To avoid that, this change explicitely moves to
base::Optional as return value:
  return base::Optional<Foo>(std::move(response));

Change-Id: Ic0390e1c31340dc34a71bb4175bd63a4631248d6
Reviewed-on: https://chromium-review.googlesource.com/944402
Commit-Queue: Victor Costan <pwnall@chromium.org>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541029}

content/browser/appcache/appcache_request_handler.cc

@@ -639,7 +639,7 @@ AppCacheRequestHandler::MaybeCreateSubresourceLoaderParams() {
 
   SubresourceLoaderParams params;
   params.loader_factory_info = factory_ptr.PassInterface();
-  return params;
+  return base::Optional<SubresourceLoaderParams>(std::move(params));
 }
 
 void AppCacheRequestHandler::MaybeCreateSubresourceLoader(

content/browser/service_worker/service_worker_controllee_request_handler.cc

@@ -271,7 +271,7 @@ ServiceWorkerControlleeRequestHandler::MaybeCreateSubresourceLoaderParams() {
   controller_info->object_info = provider_host_->GetOrCreateServiceWorkerHandle(
       provider_host_->controller());
   params.controller_service_worker_info = std::move(controller_info);
-  return params;
+  return base::Optional<SubresourceLoaderParams>(std::move(params));
 }
 
 void ServiceWorkerControlleeRequestHandler::PrepareForMainResource(

device/fido/device_response_converter.cc

@@ -121,7 +121,7 @@ base::Optional<AuthenticatorGetAssertionResponse> ReadCTAPGetAssertionResponse(
     response.SetNumCredentials(it->second.GetUnsigned());
   }
 
-  return response;
+  return base::Optional<AuthenticatorGetAssertionResponse>(std::move(response));
 }
 
 base::Optional<AuthenticatorGetInfoResponse> ReadCTAPGetInfoResponse(
@@ -241,7 +241,7 @@ base::Optional<AuthenticatorGetInfoResponse> ReadCTAPGetInfoResponse(
     response.SetPinProtocols(std::move(supported_pin_protocols));
   }
 
-  return response;
+  return base::Optional<AuthenticatorGetInfoResponse>(std::move(response));
 }
 
 }  // namespace device