afakhry@ can someone in your team take this on?

That looks like an IME issue. shuchen@ Could you please take a look? If it's something on our side, please let us know.

From my ChromeOS days I recall Neo is a stress test for keyboard handling. I would first check a layout tester like https://dvcs.w3.org/hg/d4e/raw-file/tip/key-event-test.html

I conjecture that the DOM3 key and code are correct but the Windows VK (legacy keyCode) is wrong (and is VKEY_V and VKEY_W). In that case the problem would be that XkbKeyboardLayoutEngine::Lookup() fails to handle the case of values with special VKEYs (Return & Backspace) generated from non-Control modified printable keys.

I don't have a debugging environment setup for this (the sandbox chrome os doesn't compile with ozone).

By checking the code & guessing the root cuase, I made a simple fix: 
https://codereview.chromium.org/2481413006

Kevin, can you please help to verify whether my cl can fix this issue? thanks!

#5 I'm travelling this week; I'll verify this on Tuesday.

Thanks kpschoedel@ for verification. Taking over the issue and submitting the cl.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/958f9a87ed3bf08d72839ce1e078f967ff4dabd6

commit 958f9a87ed3bf08d72839ce1e078f967ff4dabd6
Author: shuchen <shuchen@chromium.org>
Date: Fri Nov 25 00:25:09 2016

Checks the DomKey in the non-printable map to determine whether a key event is non-character.

And fallback to check the character value.

BUG= 633238 

Review-Url: https://codereview.chromium.org/2481413006
Cr-Commit-Position: refs/heads/master@{#434412}

[modify] https://crrev.com/958f9a87ed3bf08d72839ce1e078f967ff4dabd6/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc
[modify] https://crrev.com/958f9a87ed3bf08d72839ce1e078f967ff4dabd6/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine_unittest.cc

This still doesn’t work with version 55.0.2883.103 on platform 8872.73.0.

For the record, this causes chromeos/ozone use_xkbcommon=true failures to me:

FAILED: obj/ui/events/events_unittests/xkb_keyboard_layout_engine_unittest.o 
/b/c/cipd/goma/gomacc ../../third_party/llvm-build/Release+Asserts/bin/clang++ -MMD -MF obj/ui/events/events_unittests/xkb_keyboard_layout_engine_unittest.o.d -DV8_DEPRECATION_WARNINGS -DUSE_UDEV -DUI_COMPOSITOR_IMAGE_TRANSPORT -DUSE_AURA=1 -DUSE_NSS_CERTS=1 -DUSE_OZONE=1 -DFULL_SAFE_BROWSING -DSAFE_BROWSING_CSD -DSAFE_BROWSING_DB_LOCAL -DCHROMIUM_BUILD -DENABLE_MEDIA_ROUTER=1 -DFIELDTRIAL_TESTING_ENABLED -DCR_CLANG_REVISION=\"289944-2\" -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DGTEST_HAS_POSIX_RE=0 -DGTEST_LANG_CXX11=1 -DGL_GLEXT_PROTOTYPES -DUSE_GLX -DUSE_EGL -DSK_IGNORE_DW_GRAY_FIX -DSK_IGNORE_LINEONLY_AA_CONVEX_PATH_OPTS -DSK_SUPPORT_GPU=1 -DU_USING_ICU_NAMESPACE=0 -DU_ENABLE_DYLOAD=0 -DU_STATIC_IMPLEMENTATION -DICU_UTIL_DATA_IMPL=ICU_UTIL_DATA_FILE -DUNIT_TEST -DENABLE_IPC_FUZZER -DUSE_EVDEV -I../.. -Igen -I../../testing/gtest/include -I../../third_party/khronos -I../../gpu -I../../skia/config -I../../skia/ext -I../../third_party/skia/include/c -I../../third_party/skia/include/config -I../../third_party/skia/include/core -I../../third_party/skia/include/effects -I../../third_party/skia/include/images -I../../third_party/skia/include/lazy -I../../third_party/skia/include/pathops -I../../third_party/skia/include/pdf -I../../third_party/skia/include/pipe -I../../third_party/skia/include/ports -I../../third_party/skia/include/utils -I../../third_party/skia/include/gpu -I../../third_party/skia/src/gpu -I../../third_party/skia/src/sksl -I../../third_party/icu/source/common -I../../third_party/icu/source/i18n -I../../third_party/ced/src -I../../testing/gmock_custom -I../../testing/gmock/include -I../../third_party/WebKit -Igen/third_party/WebKit -I../../v8/include -Igen/v8/include -fno-strict-aliasing --param=ssp-buffer-size=4 -fstack-protector -Wno-builtin-macro-redefined -D__DATE__= -D__TIME__= -D__TIMESTAMP__= -funwind-tables -fPIC -pipe -B../../third_party/binutils/Linux_x64/Release/bin -fcolor-diagnostics -fdebug-prefix-map=/b/c/b/linux/src=. -m64 -march=x86-64 -pthread -Wall -Werror -Wextra -Wno-missing-field-initializers -Wno-unused-parameter -Wno-c++11-narrowing -Wno-covered-switch-default -Wno-deprecated-register -Wno-unneeded-internal-declaration -Wno-inconsistent-missing-override -Wno-shift-negative-value -Wno-undefined-var-template -Wno-nonportable-include-path -Wno-address-of-packed-member -O2 -fno-ident -fdata-sections -ffunction-sections -g0 --sysroot=../../build/linux/debian_jessie_amd64-sysroot -fvisibility=hidden -Xclang -load -Xclang ../../third_party/llvm-build/Release+Asserts/lib/libFindBadConstructs.so -Xclang -add-plugin -Xclang find-bad-constructs -Xclang -plugin-arg-find-bad-constructs -Xclang check-ipc -Wheader-hygiene -Wstring-conversion -Wtautological-overlap-compare -fvisibility-inlines-hidden -std=gnu++11 -fno-rtti -fno-exceptions -c ../../ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine_unittest.cc -o obj/ui/events/events_unittests/xkb_keyboard_layout_engine_unittest.o
../../ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine_unittest.cc:826:60: error: use of undeclared identifier 'VKEY_BACKSPACE'
    {{DomCode::US_W, EF_ALTGR_DOWN, XKB_KEY_BackSpace, 8}, VKEY_BACKSPACE},
                                                           ^
../../ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine_unittest.cc:827:58: error: use of undeclared identifier 'VKEY_ENTER'
    {{DomCode::US_V, EF_ALTGR_DOWN, XKB_KEY_Return, 13}, VKEY_ENTER},
                                                         ^
../../ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine_unittest.cc:829:24: error: cannot use incomplete type 'const struct (anonymous struct at ../../ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine_unittest.cc:803:16) []' as a range
  for (const auto& e : kVkeyTestCase) {
                       ^
../../ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine_unittest.cc:836:5: error: no type named 'Compare' in the global namespace
    EXPECT_EQ(e.key_code, key_code);


Build error can also be verified in the linux/ozone FYI bot: https://build.chromium.org/p/chromium.fyi/builders/Ozone%20Linux/builds/5214/steps/compile/logs/stdio

shuchen@, kpschoedel@, spang@: any ideas?

Should be VKEY_BACK and VKEY_RETURN respectively.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f2da5092fa3e87ef4a0d8111f2818148238bd06c

commit f2da5092fa3e87ef4a0d8111f2818148238bd06c
Author: tonikitoo <tonikitoo@igalia.com>
Date: Tue Feb 07 20:45:35 2017

Fix 'events_unittests' build

$ vim u/e/o/l/x/xkb_keyboard_layout_engine_unittest.cc
: %s/VKEY_BACKSPACE/VKEY_BACK/gc
: %s/VKEY_ENTER/VKEY_RETURN/gc

TBR=kpschoedel@chromium.org,spang@chromium.org

BUG= 633238 

Review-Url: https://codereview.chromium.org/2678283003
Cr-Commit-Position: refs/heads/master@{#448726}

[modify] https://crrev.com/f2da5092fa3e87ef4a0d8111f2818148238bd06c/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine_unittest.cc

This is just to confirm, that the fourth layer seems to work now, since the update from *last week*.