Roll engine 1d62160fdb2f..4a849e0f8dd5 (17 commits) (#42200)

git@github.com:flutter/engine.git/compare/1d62160fdb2f...4a849e0f8dd5

git log 1d62160fdb2f..4a849e0f8dd5 --no-merges --oneline
2019-10-08 dnfield@google.com Color matrix doc (flutter/engine#12982)
2019-10-07 jason-simmons@users.noreply.github.com Use the standard gen_snapshot target unless the platform requires host_targeting_host (flutter/engine#12988)
2019-10-07 bkonyi@google.com Roll src/third_party/dart 8413a0db0d..8ba6f7e2eb (39 commits) (flutter/engine#12981)
2019-10-07 liyuqian@google.com Unblock Fuchsia roll (flutter/engine#12977)
2019-10-06 chinmaygarde@google.com Update buildroot to pull in ubsan updates. (flutter/engine#12821)
2019-10-05 skia-flutter-autoroll@skia.org Roll src/third_party/skia 95edac1c9a4a..4c82a9fc83a5 (13 commits) (flutter/engine#12818)
2019-10-05 chinmaygarde@google.com Enable sanitizer build variants. (flutter/engine#12816)
2019-10-05 katelovett@google.com Revert "Adding Link SemanticsFlag (#12453)" (flutter/engine#12815)
2019-10-04 jason-simmons@users.noreply.github.com Use the x64 host toolchain for x86 target gen_snapshot only on Linux (flutter/engine#12809)
2019-10-04 yjbanov@google.com add option for bulk-updating screenshots; update screenshots (flutter/engine#12797)
2019-10-04 dnfield@google.com unbreak unopt fuchsia (flutter/engine#12805)
2019-10-04 jason-simmons@users.noreply.github.com Build gen_snapshot with a 64-bit host toolchain even if the target platform is 32-bit (flutter/engine#12802)
2019-10-04 dnfield@google.com [flutter_runner] a11y updates, tests! (flutter/engine#12380)
2019-10-04 WATER1350@gmail.com Fix crash in copypixelbuffer (flutter/engine#10326)
2019-10-04 bkonyi@google.com Roll src/third_party/dart d6c6d12ebf..8413a0db0d (2 commits)
2019-10-04 skia-flutter-autoroll@skia.org Roll fuchsia/sdk/core/mac-amd64 from JyZWz... to kwa2O... (flutter/engine#12803)
2019-10-04 katelovett@google.com Adding Link SemanticsFlag (flutter/engine#12453)


If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/flutter-engine-flutter-autoroll
Please CC liyuqian@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

bin/internal/engine.version

-1d62160fdb2f5a1d20f1dccb761a2caa96804c22
+4a849e0f8dd50adaf1ccf3d386a90d994ca95c55