Fix use-after-move in //c/b/webshare/

Fix use-after-move (potential) bugs found by the
"bugprone-use-after-move" clang-tidy check.

Bug: 1122844
Change-Id: I79a2c036a0f674dbedc48094b7b7ceee5d3893c3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2560633
Auto-Submit: Maksim Ivanov <emaxx@chromium.org>
Reviewed-by: Eric Willigers <ericwilligers@chromium.org>
Commit-Queue: Maksim Ivanov <emaxx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#831297}

chrome/browser/webshare/share_service_impl.cc

@@ -177,7 +177,8 @@ void ShareServiceImpl::Share(const std::string& title,
 #elif defined(OS_WIN)
   auto share_operation = std::make_unique<webshare::ShareOperation>(
       title, text, share_url, std::move(files), web_contents);
-  share_operation->Run(base::BindOnce(
+  auto* const share_operation_ptr = share_operation.get();
+  share_operation_ptr->Run(base::BindOnce(
       [](std::unique_ptr<webshare::ShareOperation> share_operation,
          ShareCallback callback,
          blink::mojom::ShareError result) { std::move(callback).Run(result); },