Add build and test configuration for new Blink Heap Incremental Marking bot.

Bug: 812533
Change-Id: I117efbfa67d65995b21530a0aa5532fa60b42cf5
Reviewed-on: https://chromium-review.googlesource.com/934622Reviewed-by: Stephen Martinis <martiniss@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#538907}

testing/buildbot/chromium.fyi.json

@@ -314,6 +314,25 @@
       }
     ]
   },
+  "Blink Heap Incremental Markup": {
+    "isolated_scripts": [
+      {
+        "isolate_name": "webkit_layout_tests_exparchive",
+        "merge": {
+          "args": [
+            "--verbose"
+          ],
+          "script": "//third_party/WebKit/Tools/Scripts/merge-layout-test-results"
+        },
+        "name": "webkit_layout_tests",
+        "results_handler": "layout tests",
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "shards": 6
+        }
+      }
+    ]
+  },
   "CFI Linux (icall)": {
     "gtest_tests": [
       {

testing/buildbot/waterfalls.pyl

@@ -903,6 +903,11 @@
         'os_type': 'android',
         'skip_output_links': True,
       },
+      'Blink Heap Incremental Markup': {
+        'test_suites': {
+          'isolated_scripts': 'chromium_webkit_isolated_scripts',
+        },
+      },
       'CFI Linux (icall)': {
         'test_suites': {
           'gtest_tests': 'chromium_linux_clang_and_gl_gtests',

tools/mb/mb_config.pyl

@@ -207,6 +207,8 @@
       'Win Goma Canary LocalOutputCache': 'release_bot_x86_minimal_symbols',
       'WinMSVC64 Goma Canary': 'win_msvc_release_bot',
 
+      'Blink Heap Incremental Marking': 'debug_bot_enable_blink_heap_incremental_marking',
+
       'EarlGreyiOS': 'ios',
       'Fuchsia (dbg)': 'debug_bot_fuchsia',
       'Fuchsia ARM64': 'release_bot_fuchsia_arm64',
@@ -1238,6 +1240,10 @@
       'debug_bot', 'arm64',
     ],
 
+    'debug_bot_enable_blink_heap_incremental_marking': [
+      'debug_bot', 'enable_blink_heap_incremental_marking',
+    ],
+
     'debug_bot_fuchsia': [
       'debug_bot', 'fuchsia',
     ],
@@ -1862,6 +1868,10 @@
       'gn_args': 'sanitizer_coverage_flags="trace-pc-guard"',
     },
 
+    'enable_blink_heap_incremental_marking': {
+      'gn_args': 'enable_blink_heap_incremental_marking=true',
+    },
+
     # This mixin is used to force configs that use it to fail. It
     # is used in two cases: when we have bots that we haven't looked
     # at yet and don't know whether they need MB or not, and for bots