Adds iOS builds for add-to-app to Travis setup (#244)

.travis.yml

@@ -1,40 +1,58 @@
-os: linux
-dist: trusty
-
-addons:
-  apt:
-    sources:
-      - ubuntu-toolchain-r-test
-    packages:
-      - libstdc++6
-      - fonts-noto
-
 git:
   depth: 3
 
-android:
-  components:
-    - build-tools-28.0.3
-    - android-28
-
 jobs:
   include:
+    - name: "iOS tests, stable channel"
+      os: osx
+      osx_image: xcode11.2
+      language: objective-c
+      script: ./tool/travis_ios_script.sh
+      env: FLUTTER_VERSION=stable
+
     - name: "Android tests, stable channel"
+      os: linux
+      dist: trusty
       language: android
+      android:
+        components:
+          - build-tools-28.0.3
+          - android-28
       script: ./tool/travis_android_script.sh
       env: FLUTTER_VERSION=stable
+
     - name: "Flutter tests, stable channel"
+      os: linux
+      dist: trusty
       language: ruby
       script: ./tool/travis_flutter_script.sh
       env: FLUTTER_VERSION=stable
+
+    - name: "iOS tests, beta channel"
+      os: osx
+      osx_image: xcode11.2
+      language: objective-c
+      script: ./tool/travis_ios_script.sh
+      env: FLUTTER_VERSION=beta
+
     - name: "Android tests, beta channel"
+      os: linux
+      dist: trusty
       language: android
+      android:
+        components:
+          - build-tools-28.0.3
+          - android-28
       script: ./tool/travis_android_script.sh
       env: FLUTTER_VERSION=beta
+
     - name: "Flutter tests, beta channel"
+      os: linux
+      dist: trusty
       language: ruby
       script: ./tool/travis_flutter_script.sh
       env: FLUTTER_VERSION=beta
+
   allow_failures:
     - env: FLUTTER_VERSION=beta
 
@@ -44,6 +62,7 @@ before_script:
   - chmod +x tool/travis_*_script.sh
 
 cache:
+  cocoapods: true
   directories:
     - $HOME/shared/.pub-cache