feat(chromium): roll Chromium to r620317 (#3732)

This roll includes:
- https://crrev.com/619087 - DevTools: support interception for file: schema
- https://crrev.com/616936 - Complete the screen capture color space plumbing

This should allow us to switch to network service by default.

Note: We now have to force a specific color space since https://crrev.com/616936
tries to pick the system one.

lib/Launcher.js

@@ -50,6 +50,7 @@ const DEFAULT_ARGS = [
   '--disable-renderer-backgrounding',
   '--disable-sync',
   '--disable-translate',
+  '--force-color-profile=srgb',
   '--metrics-recording-only',
   '--no-first-run',
   '--safebrowsing-disable-auto-update',

package.json

@@ -8,7 +8,7 @@
     "node": ">=6.4.0"
   },
   "puppeteer": {
-    "chromium_revision": "615489"
+    "chromium_revision": "620317"
   },
   "scripts": {
     "unit": "node test/test.js",