Add browser_tests, content_browsertests and extensions_browsertests to WebKit Linux Oilpan

testing/buildbot/chromium.webkit.json

Index: testing/buildbot/chromium.webkit.json
diff --git a/testing/buildbot/chromium.webkit.json b/testing/buildbot/chromium.webkit.json
index 86e83f429ffce893e3ca57d97e78fbbd0a9c8fc4..0e32301135845e272e894d9df23bd3502dc26b9e 100644
--- a/testing/buildbot/chromium.webkit.json
+++ b/testing/buildbot/chromium.webkit.json
@@ -840,6 +840,25 @@
       },
       {
         "swarming": {
+          "can_use_on_swarming_builders": true,
+          "shards": 20
+        },
+        "test": "browser_tests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
+        "test": "content_browsertests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
+        "test": "extensions_browsertests"
+      },
+      {
+        "swarming": {
           "can_use_on_swarming_builders": true
         },
         "test": "webkit_unit_tests"