Added buildbot test configs for WebView O CTS bot

Bug: 839172
Change-Id: I9881db40caa593819cfaaf686a8e24ab0dc8bc4e
Reviewed-on: https://chromium-review.googlesource.com/1041158Reviewed-by: Ben Pastene <bpastene@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Andrew Luo <aluo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555852}

testing/buildbot/chromium.android.json

@@ -514,6 +514,14 @@
       }
     ]
   },
+  "Android WebView O (dbg)": {
+    "cts_tests": [
+      {
+        "arch": "arm64",
+        "platform": "O"
+      }
+    ]
+  },
   "Android arm Builder (dbg)": {
     "additional_compile_targets": [
       "dump_syms",

testing/buildbot/test_suites.pyl

@@ -38,6 +38,11 @@
     'platform': 'N',
   },
 
+  'android_o_cts_tests': {
+    'arch': 'arm64',
+    'platform': 'O',
+  },
+
   'android_fyi_instrumentation_tests': {
     'chrome_public_test_apk': {},
     'chrome_sync_shell_test_apk': {},

testing/buildbot/waterfalls.pyl

@@ -163,6 +163,13 @@
         'use_swarming': False,
         'os_type': 'android',
       },
+      'Android WebView O (dbg)': {
+        'test_suites': {
+          'cts_tests': 'android_o_cts_tests',
+        },
+        'use_swarming': False,
+        'os_type': 'android',
+      },
       'KitKat Phone Tester (dbg)': {
         'test_suites': {
           'gtest_tests': 'chromium_android_gtests',