Roll chromium_revision 374735e0c4..8557f6fd65 (439777:439808)

Change log: https://chromium.googlesource.com/chromium/src/+log/374735e0c4..8557f6fd65
Full diff: https://chromium.googlesource.com/chromium/src/+/374735e0c4..8557f6fd65

No dependencies changed.
No update to Clang.

TBR=
BUG=None

Review-Url: https://codereview.webrtc.org/2588373003
Cr-Commit-Position: refs/heads/master@{#15716}
diff --git a/DEPS b/DEPS
index 75c9235..ce20415 100644
--- a/DEPS
+++ b/DEPS
@@ -5,7 +5,7 @@
 
 vars = {
   'chromium_git': 'https://chromium.googlesource.com',
-  'chromium_revision': '374735e0c4263d52a2dc8409e33773cf071fb20b',
+  'chromium_revision': '8557f6fd655f9f0f62666721c7176d3d3c1e77f7',
 }
 
 deps = {