WebUI: Add dschuyler@ to PLATFORM_OWNERS file.

Bug: NONE
Change-Id: I855af0b5ad1f729c42a2661d542dc178f388793a
Reviewed-on: https://chromium-review.googlesource.com/595028Reviewed-by: Dave Schuyler <dschuyler@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Tommy Li <tommycli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#490812}

ui/base/webui/OWNERS

 file://ui/webui/PLATFORM_OWNERS
 
-dschuyler@chromium.org
-
 # COMPONENT: UI>Browser>WebUI

ui/webui/PLATFORM_OWNERS

@@ -2,6 +2,7 @@
 bauerb@chromium.org
 calamity@chromium.org
 dpapad@chromium.org
+dschuyler@chromium.org
 michaelpg@chromium.org
 pam@chromium.org
 tommycli@chromium.org