[devtools] Support different encodings for Page.CaptureScreenshot.

testing/buildbot/chromium.linux.json

Index: testing/buildbot/chromium.linux.json
diff --git a/testing/buildbot/chromium.linux.json b/testing/buildbot/chromium.linux.json
index e71cdc851245ec4180c8708294f5e4676e54e6ac..1780ab1da20e8252ac99f36b7be0da386ad56ae4 100644
--- a/testing/buildbot/chromium.linux.json
+++ b/testing/buildbot/chromium.linux.json
@@ -3125,6 +3125,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "snapshot_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "sql_unittests"
       },
       {
@@ -3715,6 +3721,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "snapshot_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "sql_unittests"
       },
       {
@@ -4102,6 +4114,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "snapshot_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "sql_unittests"
       },
       {