Update repo tooling (#344)

Updates to better align with the current flutter/plugins tooling:
- Pulls the latest flutter_plugin_tools
- Enables the new version-check functionality
- Enables the new license-check functionality
- Switches over to the new publish check functionality
- Moves format checking to a bot that does several of the very fast
  checks, leaving tests as their own bot
- Switches incremental_build.sh to use the new --run-on-changed-packages
  functionality instead of the bash check_changed_packages
- Moves check_changed_packages into local_tests.sh to minimize the
  chances of future new code trying to use it, as it is now legacy.
- Renames incremental_build.sh to tool_runner.sh, to better match its
  current behavior/use

script/local_tests.sh

@@ -2,13 +2,52 @@
 # Copyright 2013 The Flutter Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
+
+# TODO(stuartmorgan): Replace this script either with flutter_plugin_tools
+# functionality, or something pigeon-specific, to eliminate the need to have a
+# bash copy of checked_changed_packages in this repository.
 set -e
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null && pwd)"
 REPO_DIR="$(dirname "$SCRIPT_DIR")"
 TEST_SCRIPT_NAME="run_tests.sh"
 
-source "$SCRIPT_DIR/common.sh"
+function check_changed_packages() {
+  # Try get a merge base for the branch and calculate affected packages.
+  # We need this check because some CIs can do a single branch clones with a limited history of commits.
+  local packages
+  local branch_base_sha="$(git merge-base --fork-point FETCH_HEAD HEAD || git merge-base FETCH_HEAD HEAD)"
+  if [[ "$?" == 0 ]]; then
+    echo "Checking for changed packages from $branch_base_sha"
+    IFS=$'\n' packages=( $(git diff --name-only "$branch_base_sha" HEAD | grep -o "packages/[^/]*" | sed -e "s/packages\///g" | sort | uniq) )
+  else
+    error "Cannot find a merge base for the current branch to run an incremental build..."
+    error "Please rebase your branch onto the latest master!"
+    return 1
+  fi
+
+  # Filter out any packages that don't have a pubspec.yaml: they have probably
+  # been deleted in this PR.
+  CHANGED_PACKAGES=""
+  CHANGED_PACKAGE_LIST=()
+  for package in "${packages[@]}"; do
+    if [[ -f "$REPO_DIR/packages/$package/pubspec.yaml" ]]; then
+      CHANGED_PACKAGES="${CHANGED_PACKAGES},$package"
+      CHANGED_PACKAGE_LIST=("${CHANGED_PACKAGE_LIST[@]}" "$package")
+    fi
+  done
+
+  if [[ "${#CHANGED_PACKAGE_LIST[@]}" == 0 ]]; then
+    echo "No changes detected in packages."
+  else
+    echo "Detected changes in the following ${#CHANGED_PACKAGE_LIST[@]} package(s):"
+    for package in "${CHANGED_PACKAGE_LIST[@]}"; do
+      echo "$package"
+    done
+    echo ""
+  fi
+  return 0
+}
 
 check_changed_packages