[device doctor] Use dart sdk beta to build (#1851)

diff --git a/.ci.yaml b/.ci.yaml
index 38df5bb..ecea1bf 100644
--- a/.ci.yaml
+++ b/.ci.yaml
@@ -14,7 +14,8 @@
       os: Linux
   mac:
     properties:
-      os: Mac-10.15
+      os: Mac-12
+      cpu: x86
   windows:
     properties:
       os: Windows
@@ -32,6 +33,7 @@
       add_recipes_cq: "true"
     runIf:
       - device_doctor/**
+      - .ci.yaml
 
   - name: Mac device_doctor
     postsubmit: false
@@ -40,6 +42,7 @@
       add_recipes_cq: "true"
     runIf:
       - device_doctor/**
+      - .ci.yaml
 
   - name: Windows device_doctor
     postsubmit: false
@@ -48,6 +51,7 @@
       add_recipes_cq: "true"
     runIf:
       - device_doctor/**
+      - .ci.yaml
 
   - name: Linux ci_yaml roller
     recipe: infra/ci_yaml
diff --git a/app_dart/integration_test/data/cocoon_config.json b/app_dart/integration_test/data/cocoon_config.json
index 14d4146..06a0544 100644
--- a/app_dart/integration_test/data/cocoon_config.json
+++ b/app_dart/integration_test/data/cocoon_config.json
@@ -1 +1 @@
-{"targets":[{"name":"Linux Cocoon","properties":{"add_recipes_cq":"true"},"recipe":"cocoon/cocoon"},{"name":"Linux device_doctor","properties":{"add_recipes_cq":"true"},"postsubmit":false,"runIf":["device_doctor/**"],"recipe":"cocoon/device_doctor"},{"name":"Mac device_doctor","properties":{"add_recipes_cq":"true"},"postsubmit":false,"runIf":["device_doctor/**"],"recipe":"cocoon/device_doctor"},{"name":"Windows device_doctor","properties":{"add_recipes_cq":"true"},"postsubmit":false,"runIf":["device_doctor/**"],"recipe":"cocoon/device_doctor"},{"name":"Linux ci_yaml roller","properties":{"add_recipes_cq":"true"},"recipe":"infra/ci_yaml"}],"enabledBranches":["main"],"platformProperties":{"linux":{"properties":{"os":"Linux"}},"mac":{"properties":{"os":"Mac-10.15"}},"windows":{"properties":{"os":"Windows"}}}}
+{"targets":[{"name":"Linux Cocoon","properties":{"add_recipes_cq":"true"},"recipe":"cocoon/cocoon"},{"name":"Linux device_doctor","properties":{"add_recipes_cq":"true"},"postsubmit":false,"runIf":["device_doctor/**",".ci.yaml"],"recipe":"cocoon/device_doctor"},{"name":"Mac device_doctor","properties":{"add_recipes_cq":"true"},"postsubmit":false,"runIf":["device_doctor/**",".ci.yaml"],"recipe":"cocoon/device_doctor"},{"name":"Windows device_doctor","properties":{"add_recipes_cq":"true"},"postsubmit":false,"runIf":["device_doctor/**",".ci.yaml"],"recipe":"cocoon/device_doctor"},{"name":"Linux ci_yaml roller","properties":{"add_recipes_cq":"true"},"recipe":"infra/ci_yaml"}],"enabledBranches":["main"],"platformProperties":{"linux":{"properties":{"os":"Linux"}},"mac":{"properties":{"os":"Mac-12","cpu":"x86"}},"windows":{"properties":{"os":"Windows"}}}}
diff --git a/device_doctor/tool/build.sh b/device_doctor/tool/build.sh
index e7eb3ae..4099dd5 100644
--- a/device_doctor/tool/build.sh
+++ b/device_doctor/tool/build.sh
@@ -28,7 +28,7 @@
 fi
 
 mkdir -p build
-tool/dart-sdk/bin/pub get
+tool/dart-sdk/bin/dart pub get
 tool/dart-sdk/bin/dart compile exe bin/main.dart -o build/device_doctor
 
 cp -f LICENSE build/
diff --git a/device_doctor/tool/ensure_file b/device_doctor/tool/ensure_file
index b537e1f..a6985f8 100644
--- a/device_doctor/tool/ensure_file
+++ b/device_doctor/tool/ensure_file
@@ -1,3 +1,3 @@
 $ServiceURL https://chrome-infra-packages.appspot.com/
 
-dart/dart-sdk/${os}-${arch} stable
+dart/dart-sdk/${os}-${arch} beta