Firebase hosting for docs (#4871)

* configs for firebase hosting

* use the implicit FIREBASE_TOKEN

* don't print every command (lowers the chance of printing secret env vars, and for realz only deploy when merging into master

dev/bots/docs.sh

@@ -1,5 +1,5 @@
 #!/bin/bash
-set -ex
+set -e
 
 # Install dartdoc.
 pub global activate dartdoc
@@ -14,7 +14,9 @@ dart dev/tools/dartdoc.dart
 # Ensure google webmaster tools can verify our site.
 cp dev/docs/google2ed1af765c529f57.html dev/docs/doc
 
-# Upload the docs.
+# Upload the docs to cloud storage.
+# TODO: remove this when we're comfortable with Firebase hosting.
+
 if [ "$1" = "--upload" ]; then
   # This isn't great, because we're uploading our files twice. But,
   # we're ensuring we're not leaving any deleted files on the server.
@@ -29,3 +31,12 @@ if [ "$1" = "--upload" ]; then
   # Ensure compressable files are gzipped and then stored.
   gsutil -m cp -r -z "js,json,html,css" dev/docs/doc/* gs://docs.flutter.io/
 fi
+
+# Upload new API docs when on Travis and branch is master
+
+if [ "$TRAVIS_PULL_REQUEST" = "false" ]; then
+  if [ "$TRAVIS_BRANCH" = "master" ]; then
+    cd dev/docs
+    firebase deploy --project docs-flutter-io
+  fi
+fi

dev/bots/test.sh

@@ -53,3 +53,6 @@ if [ -n "$COVERAGE_FLAG" ]; then
   STORAGE_URL=gs://flutter_infra/flutter/coverage/lcov.info
   $GSUTIL cp packages/flutter/coverage/lcov.info $STORAGE_URL
 fi
+
+# generate the API docs, upload them
+dev/bots/docs.sh