DevTools: dtrun CLI helper

third_party/WebKit/Source/devtools/readme.md

 # Chrome DevTools frontend
 
 The client-side of the Chrome DevTools, including all JS & CSS to run the DevTools webapp.
 
 It is available on NPM as the [chrome-devtools-frontend](https://www.npmjs.com/package/chrome-devtools-frontend) package. It's not currently available via CJS or ES2015 modules, so consuming this package in other tools may require [some effort](https://github.com/paulirish/devtools-timeline-model/blob/master/index.js).
 
 #### Package versioning
 The version number of the npm package (e.g. `1.0.373466`) refers to the Chromium commit position of latest frontend git commit. It's incremented with every Chromium commit, however the package is updated roughly daily.
 
 ### Source code
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 > ```
 
 ### Hacking
 * DevTools documentation: [devtools.chrome.com](https://devtools.chrome.com)
 * [Debugging protocol docs](https://developer.chrome.com/devtools/docs/debugger-protocol) and [Chrome Debugging Protocol Viewer](http://chromedevtools.github.io/debugger-protocol-viewer/)
 * [awesome-chrome-devtools](https://github.com/paulirish/awesome-chrome-devtools): recommended tools and resources
 * Contributing to DevTools: [bit.ly/devtools-contribution-guide](http://bit.ly/devtools-contribution-guide)
 
 ### Useful Commands
 
-Basic:
-* `npm run format` - formats your code using clang-format
-* `npm test` - builds devtools and runs all inspector layout tests
+#### Simpler npm commands w/ `dtrun`
+If you want to run these npm commands anywhere in the chromium repo (e.g. in chromium/src), you'll want to setup our `dtrun` CLI helper.
+
+One-time setup:
+```
+npm run setup-dtrun
+```
+
+Now, you can use any of the following commands by simply doing: `dtrun test`. 
+
+In addition, you no longer need to pass double dashes (e.g. `--`) before you pass in the flags. So you can do: `dtrun test -d inspector/test.html`.
+
+#### `npm run format` 
+Formats your code using clang-format
+
+#### `npm test`
+Builds devtools and runs all inspector/devtools layout tests.
 
 > Note: If you're using a full chromium checkout and compiled content shell in out/Release, then `npm test` uses that. Otherwise, with only a front-end checkout (i.e. cloning from GitHub), then `npm test` will fetch a previously compiled content shell from the cloud (and cache it for future test runs).
 
-Advanced testing:
-* `npm test -- --fetch-content-shell` - even if you're using a full chromium checkout and have a compiled content shell, this will fetch a pre-compiled content shell. This is useful if you haven't compiled your content shell recently.
-* `npm test -- -f --child-processes=16` - pass in additional flags to the test harness
-* `npm test -- inspector/sources inspector/console` - run specific tests
-* `npm test -- inspector/cookie-resource-match.html --debug-devtools` OR `npm run debug-test inspector/cookie-resource-match.html` - debug a specific test (non-bundled & minified). You can use "-d" as a shorthand for "--debug-devtools".
+#### `npm test` basics
+```
+# run specific tests
+npm test -- inspector/sources inspector/console
 
-#### Development
+# debug a specific test. Any one of:
+npm run debug-test inspector/cookie-resource-match.html
+npm test -- --debug-devtools inspector/cookie-resource-match.html 
+npm test -- -d inspector/cookie-resource-match.html 
+
+# pass in additional flags to the test harness
+npm test -- -f --child-processes=16
+
+# ...for example, use a higher test timeout
+npm test -- --time-out-ms=6000000 <test_path>
+```
+
+> **Tip**: [Learn about the test harness flags](https://chromium.googlesource.com/chromium/src/+/master/docs/testing/layout_tests.md#Test-Harness-Options)
+
+#### `--fetch-content-shell`
+```
+# If you're using a full chromium checkout and have a compiled content shell, 
+# this will fetch a pre-compiled content shell. This is useful if you 
+# haven't compiled your content shell recently
+npm test -- --fetch-content-shell
+```
+
+### Development
 * All devtools commits: [View the log], [RSS feed] or [@DevToolsCommits] on Twitter
 * [All open DevTools tickets] on crbug.com
 * File a new DevTools ticket: [new.crbug.com](https://bugs.chromium.org/p/chromium/issues/entry?labels=OS-All,Type-Bug,Pri-2&components=Platform%3EDevTools)
 * Code reviews mailing list: [devtools-reviews@chromium.org]
 
 ### Getting in touch
 * [@ChromeDevTools] on Twitter
 * Chrome DevTools mailing list: [groups.google.com/forum/google-chrome-developer-tools](https://groups.google.com/forum/#!forum/google-chrome-developer-tools)
 
   [devtools-reviews@chromium.org]: https://groups.google.com/a/chromium.org/forum/#!forum/devtools-reviews
   [RSS feed]: https://feeds.peter.sh/chrome-devtools/
   [View the log]: https://chromium.googlesource.com/chromium/src/third_party/WebKit/Source/devtools/+log/master
   [@ChromeDevTools]: http://twitter.com/ChromeDevTools
   [@DevToolsCommits]: http://twitter.com/DevToolsCommits
   [all open DevTools tickets]: https://bugs.chromium.org/p/chromium/issues/list?can=2&q=component%3APlatform%3EDevTools&sort=&groupby=&colspec=ID+Stars+Owner+Summary+Modified+Opened