Run canary tests in presubmit

tool/browser_test.sh

+#!/bin/bash
+
+# Check that node exists and refers to nodejs
+checknodejs=$(hash node 2> /dev/null  && node --help | grep nodejs)
+if [[ $? -ne 0 ]]; then
+  echo 'NodeJS (node) is not properly installed'
+  echo 'Note, on Ubuntu / Debian, you may need to also install:'
+  echo '$ sudo apt-get install nodejs-legacy'
+  exit 1
+fi
+
+# Check that npm is installed
+checknpm=$(hash npm 2> /dev/null)
+if [[ $? -ne 0 ]]; then
+  echo 'Node Package Manager (npm) is not properly installed'
+  exit 1
+fi
+
+# Check for Chrome Canary on Ubuntu
+# The default install path is sometimes google-chrome-unstable
+# instead of google-chrome-canary as karma expects.
+if [[ "$OSTYPE" == "linux-gnu" ]] && [[ -z "$CHROME_CANARY_BIN" ]]; then
+  checkcanary=$(hash google-chrome-canary 2> /dev/null)
+  if [[ $? -ne 0 ]]; then
+    checkunstable=$(hash google-chrome-unstable 2> /dev/null)
+    if [[ $? -ne 0 ]]; then
+      echo 'Chrome Canary is not found'
+      echo 'Please install and/or set CHROME_CANARY_BIN to its path'
+      exit 1
+    else
+      export CHROME_CANARY_BIN=google-chrome-unstable
+    fi
+  fi
+fi
+
+npm install
+npm test