Update DevTools DEPS (trusted)

Rolling build: https://chromium.googlesource.com/chromium/src/build/+log/d377c7d..991d6cf

Roll created at https://cr-buildbucket.appspot.com/build/8732653563833860977

Bug: none
Change-Id: I5806416abc2efecc8879feeb74653e813f109bf0
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/5978363
Bot-Commit: Devtools Autoroller <devtools-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Devtools Autoroller <devtools-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>

Author: devtools-ci-autoroll-builder

DEPS

@@ -12,7 +12,7 @@ vars = {
   'build_with_chromium': False,
 
   'build_url': 'https://chromium.googlesource.com/chromium/src/build.git',
-  'build_revision': 'd377c7da034f4286eeaa0d23ffe3c76add4fa024',
+  'build_revision': '991d6cf303d1a4ff7c0edc9a0fd1265da1930ace',
 
   'buildtools_url': 'https://chromium.googlesource.com/chromium/src/buildtools.git',
   'buildtools_revision': 'de2e80e6bcf84e27c67c025c2f828a1a93df5861',