tests(viewer): don't override puppeteer's chromium (#9877)

.travis.yml

@@ -17,10 +17,10 @@ cache:
 install:
  # Ensure we have the latest Chrome stable.
  - google-chrome-stable --version
- # if our e2e tests fail in the future it might be that we are not compatible
- # with the latest puppeteer api so we probably need to run on chromimum
- # @see https://github.com/GoogleChrome/lighthouse/pull/4640/files#r171425004
- - export PUPPETEER_SKIP_CHROMIUM_DOWNLOAD=1
+ # We used to set PUPPETEER_SKIP_CHROMIUM_DOWNLOAD, but we don't want to anymore.
+ # Explicitly unset b/c environment variables seem to linger in travis.
+ # see https://github.com/GoogleChrome/lighthouse/pull/9877#discussion_r338389765
+ - unset PUPPETEER_SKIP_CHROMIUM_DOWNLOAD
  - yarn --frozen-lockfile
 before_script:
  # see comment above about puppeteer

lighthouse-viewer/test/viewer-test-pptr.js

@@ -62,7 +62,6 @@ describe('Lighthouse Viewer', () => {
  // start puppeteer
  browser = await puppeteer.launch({
  headless: true,
- executablePath: process.env.CHROME_PATH,
  });
  viewerPage = await browser.newPage();
  viewerPage.on('pageerror', pageError => pageErrors.push(pageError));