[AW] Use ScopedFD when reading finch seeds in WebView

This CL fixes a missing close() call in VariationsSeedLoader by using
ScopedFD instead of a raw int when opening the seed file.

Bug: 1138713
Change-Id: I547769c6385507cbe8fc876eb233dd0eacdb2d6a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2519741Reviewed-by: Changwan Ryu <changwan@chromium.org>
Commit-Queue: Robbie McElrath <rmcelrath@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826530}

android_webview/browser/variations/variations_seed_loader.cc

@@ -13,6 +13,7 @@
 #include "base/android/jni_string.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
+#include "base/files/scoped_file.h"
 
 using base::android::ConvertJavaStringToUTF8;
 using base::android::ConvertUTF8ToJavaString;
@@ -29,8 +30,8 @@ static jboolean JNI_VariationsSeedLoader_ParseAndSaveSeedProto(
   std::unique_ptr<AwVariationsSeed> seed =
       std::make_unique<AwVariationsSeed>(AwVariationsSeed::default_instance());
   std::string native_seed_path = ConvertJavaStringToUTF8(seed_path);
-  int seed_fd = open(native_seed_path.c_str(), O_RDONLY);
-  if (!seed->ParseFromFileDescriptor(seed_fd)) {
+  base::ScopedFD seed_fd(open(native_seed_path.c_str(), O_RDONLY));
+  if (!seed->ParseFromFileDescriptor(seed_fd.get())) {
     return false;
   }