Remove uses of BodyAsStringCallbackDeprecated (components/, pt. 1)

Updates multiple existing uses of the version of
SimpleURLLoader::DownloadToStringOfUnboundedSizeUntilCrashAndDie that
takes a BodyAsStringCallbackDeprecated to use the version that takes a
BodyAsStringCallback. This primarily involves updating the callback
function to accept a std::optional<std::string> instead of a
std::unique_ptr<std::string>. This CL touches the first half of the
components/ uses.

Bug: 40258809
Change-Id: Ic45635114ec85257bd7506c510b8bfe0655c7eeb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7169903
Commit-Queue: Andrew Williams <awillia@chromium.org>
Reviewed-by: Maks Orlovich <morlovich@chromium.org>
Owners-Override: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1549391}
NOKEYCHECK=True
GitOrigin-RevId: 460bab4c557005f9345d3ca8f029d80d2549efb7

net/net_metrics_log_uploader.cc

diff --git a/net/net_metrics_log_uploader.cc b/net/net_metrics_log_uploader.cc
index 182be8d..7581967 100644
--- a/net/net_metrics_log_uploader.cc
+++ b/net/net_metrics_log_uploader.cc
@@ -4,7 +4,9 @@
 
 #include "components/metrics/net/net_metrics_log_uploader.h"
 
+#include <optional>
 #include <sstream>
+#include <string>
 #include <string_view>
 
 #include "base/base64.h"
@@ -592,7 +594,7 @@
 
 // The callback is only invoked if |url_loader_| it was bound against is alive.
 void NetMetricsLogUploader::OnURLLoadComplete(
-    std::unique_ptr<std::string> response_body) {
+    std::optional<std::string> response_body) {
   int response_code = -1;
   if (url_loader_->ResponseInfo() && url_loader_->ResponseInfo()->headers) {
     response_code = url_loader_->ResponseInfo()->headers->response_code();

net/net_metrics_log_uploader.h

diff --git a/net/net_metrics_log_uploader.h b/net/net_metrics_log_uploader.h
index 92b1697..1a13311 100644
--- a/net/net_metrics_log_uploader.h
+++ b/net/net_metrics_log_uploader.h
@@ -6,6 +6,7 @@
 #define COMPONENTS_METRICS_NET_NET_METRICS_LOG_UPLOADER_H_
 
 #include <memory>
+#include <optional>
 #include <string>
 #include <string_view>
 
@@ -73,7 +74,7 @@
   // the payload.
   void HTTPFallbackAborted();
 
-  void OnURLLoadComplete(std::unique_ptr<std::string> response_body);
+  void OnURLLoadComplete(std::optional<std::string> response_body);
 
   // The URLLoader factory for loads done using the network stack.
   scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory_;