[reland] SkMetaData: move from src/ to tools/

Original: https://skia-review.googlesource.com/c/skia/+/227436
Change-Id: Iec326027319f39b0402e1b5c03b327cb26249159
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/227778
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index 1399990..5010b05 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1636,6 +1636,8 @@
       "tools/LsanSuppressions.cpp",
       "tools/ProcStats.cpp",
       "tools/Resources.cpp",
+      "tools/SkMetaData.cpp",
+      "tools/SkMetaData.h",
       "tools/SkSharingProc.cpp",
       "tools/ToolUtils.cpp",
       "tools/UrlDataManager.cpp",