Isolate extensions_unittests.

testing/buildbot/chromium.fyi.json

Index: testing/buildbot/chromium.fyi.json
diff --git a/testing/buildbot/chromium.fyi.json b/testing/buildbot/chromium.fyi.json
index 3e35b386cbe2617c9d79a8f3f23118ba6531eb49..536d6f889c1c93128f1d69f40301cfc62b5399f4 100644
--- a/testing/buildbot/chromium.fyi.json
+++ b/testing/buildbot/chromium.fyi.json
@@ -246,6 +246,9 @@
         "test": "events_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -416,6 +419,9 @@
         "test": "extensions_browsertests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -548,6 +554,9 @@
         "test": "crypto_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -716,6 +725,9 @@
         "test": "crypto_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -885,6 +897,9 @@
         "test": "device_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -1016,6 +1031,9 @@
         "test": "device_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -1147,6 +1165,9 @@
         "test": "device_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -1278,6 +1299,9 @@
         "test": "device_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -1409,6 +1433,9 @@
         "test": "device_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -1540,6 +1567,9 @@
         "test": "device_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -1673,6 +1703,9 @@
         "test": "device_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -1815,6 +1848,9 @@
         "test": "device_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -1955,6 +1991,9 @@
         "test": "device_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -2086,6 +2125,9 @@
         "test": "device_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -2217,6 +2259,9 @@
         "test": "device_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -2348,6 +2393,9 @@
         "test": "device_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -2460,6 +2508,9 @@
         "test": "device_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -2585,6 +2636,9 @@
         "test": "device_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -2716,6 +2770,9 @@
         "test": "device_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -2895,6 +2952,9 @@
         "test": "events_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {
@@ -3300,6 +3360,9 @@
         "test": "events_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "extensions_unittests"
       },
       {