CI: use Chrome over firefox (#15)

Author: kevmoo

.travis.yml

@@ -5,11 +5,21 @@ dart:
 - dev
 
 dart_task:
-  - dartfmt
-  - dartanalyzer
   - test: --platform vm
     xvfb: false
-  - test: --platform firefox
+  - test: --platform chrome
+
+jobs:
+  include:
+  # Only validate formatting using the dev release
+  - dart: dev
+    dart_task: dartfmt
+  - dart: dev
+    dart_task:
+      dartanalyzer: --fatal-infos --fatal-warnings .
+  - dart: 2.8.4
+    dart_task:
+      dartanalyzer: --fatal-warnings .
 
 # Only building master means that we don't run two builds for each pull request.
 branches: