Add watchlist stack_sampling_profiler

Bug: 851163
Change-Id: Id6f2b0abc70fc70ae48ee398fbd5e8afadbeca6d
Reviewed-on: https://chromium-review.googlesource.com/1216848Reviewed-by: Mike Wittman <wittman@chromium.org>
Commit-Queue: Xi Cheng <chengx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590033}

WATCHLISTS

@@ -1455,6 +1455,9 @@
                   '|third_party/hunspell/'\
                   '|third_party/hunspell_dictionaries/',
     },
+    'stack_sampling_profiler': {
+      'filepath': 'components/metrics/*call_stack_profile*',
+    },
     'startup': {
       'filepath': 'chrome/browser/ui/startup/',
     },
@@ -2350,6 +2353,7 @@
                    'rlp+watch@chromium.org',
                    'rouslan+spell@chromium.org',
                    'timvolodine@chromium.org'],
+    'stack_sampling_profiler': ['chengx+watch@chromium.org'],
     'startup': ['grt+watch@chromium.org',
                 'pastarmovj+watch@chromium.org'],
     'streams': ['zork+watch@chromium.org'],