Roll src/third_party/skia a9d9de4:7404c09

Summary of changes available at:
https://chromium.googlesource.com/skia/+log/a9d9de4..7404c09

CQ_EXTRA_TRYBOTS=tryserver.blink:linux_blink_rel,linux_blink_dbg
TBR=stephana@google.com

Review URL: https://codereview.chromium.org/902773002

Cr-Commit-Position: refs/heads/master@{#314769}

DEPS

@@ -42,7 +42,7 @@ vars = {
   'boringssl_git': 'https://boringssl.googlesource.com',
   'libvpx_revision': '5cdd30205301c293be6160f778bce981300b5a28',
   'sfntly_revision': '1bdaae8fc788a5ac8936d68bf24f37d977a13dac',
-  'skia_revision': 'a9d9de45c1cd83419b4afc7884359e92bc173009',
+  'skia_revision': '7404c0991d4389c8415cf11a6e682b17f3bce70b',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling Skia
   # and V8 without interference from each other.