Add print preview watchlist

Change-Id: I05b9c19cba0130bae74cc57f45c735d40a515c20
Reviewed-on: https://chromium-review.googlesource.com/1160856Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580533}

WATCHLISTS

@@ -1353,6 +1353,10 @@
                   '|third_party/WebKit/LayoutTests/presentation/' \
                   '|third_party/blink/renderer/modules/presentation/'
     },
+    'print_preview': {
+      'filepath': 'chrome/browser/resources/print_preview/' \
+                  '|chrome/browser/ui/webui/print_preview/'
+    },
     'push_messaging': {
       'filepath': 'push_messaging'
     },
@@ -2271,6 +2275,7 @@
     'prerender': ['gavinp+prer@chromium.org',
                   'tburkard+watch@chromium.org'],
     'presentation': ['mfoltz+watch@chromium.org'],
+    'print_preview': ['rbpotter@chromium.org'],
     'push_messaging': ['awdf+watch@chromium.org',
                        'peter@chromium.org'],
     'reading_list': ['stkhapugin@chromium.org'],