Roll chromium_revision 56d4322..78fd1c0 (358550:358554)

Change log: https://chromium.googlesource.com/chromium/src/+log/56d4322..78fd1c0
Full diff: https://chromium.googlesource.com/chromium/src/+/56d4322..78fd1c0

No dependencies changed.
No update to Clang.

TBR=
CQ_EXTRA_TRYBOTS=tryserver.webrtc:win_baremetal,mac_baremetal,linux_baremetal

Review URL: https://codereview.webrtc.org/1418733003

Cr-Commit-Position: refs/heads/master@{#10556}
diff --git a/DEPS b/DEPS
index c6fef28..1b459fd 100644
--- a/DEPS
+++ b/DEPS
@@ -6,7 +6,7 @@
 vars = {
   'extra_gyp_flag': '-Dextra_gyp_flag=0',
   'chromium_git': 'https://chromium.googlesource.com',
-  'chromium_revision': '56d4322188c7d4fd55d081a861c04d6165b0650b',
+  'chromium_revision': '78fd1c0964bcb02f305a9c823c8c2e2156bc2870',
 }
 
 # NOTE: Prefer revision numbers to tags for svn deps. Use http rather than