Add DIR_METADATA files to some directories under //third_party

Generate DIR_METADATA files and remove metadata from OWNERS
files for some directories under //third_party.

Bug: 1113033
Change-Id: I8d194fbc92282d01d7d1f7031d450587a743fd7e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2577615
Commit-Queue: Dirk Pranke <dpranke@google.com>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Auto-Submit: Edward Lesmes <ehmaldonado@chromium.org>
Cr-Commit-Position: refs/heads/master@{#834434}
GitOrigin-RevId: 15996b5d2322b634f4197447b10289bddc2b0b32
diff --git a/DIR_METADATA b/DIR_METADATA
new file mode 100644
index 0000000..a0e30b3
--- /dev/null
+++ b/DIR_METADATA
@@ -0,0 +1,3 @@
+monorail: {
+  component: "Blink>XML"
+}
diff --git a/OWNERS b/OWNERS
index 494e9ef..a15eaa2 100644
--- a/OWNERS
+++ b/OWNERS
@@ -3,5 +3,3 @@
 dcheng@chromium.org
 schenney@chromium.org
 palmer@chromium.org
-
-# COMPONENT: Blink>XML