bsittler@ I'm unable to repro on my canary samus on 55.0.2882.0 8884.  Does this happen for all profiles? Or in guest mode?  I'm trying to figure out what could be triggering it.

I have some of the Material Design flags enabled. Perhaps it's one of those? Full about: output:

Google Inc.
Copyright 2016 Google Inc. All rights reserved.
Google Chrome	55.0.2882.0 (Official Build) canary (64-bit)
Revision	0
Platform	8884.0.0 (Official Build) canary-channel samus
ARC	3335565
JavaScript	V8 5.5.372
Flash	23.0.0.185-r1
User Agent	Mozilla/5.0 (X11; CrOS x86_64 8884.0.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2882.0 Safari/537.36
Command Line	/opt/google/chrome/chrome --ppapi-flash-path=/opt/google/chrome/pepper/libpepflashplayer.so --ppapi-flash-version=23.0.0.185-r1 --ui-prioritize-in-gpu-process --use-gl=egl --enable-native-gpu-memory-buffers --gpu-sandbox-failures-fatal=yes --arc-available --enable-arc --enable-logging --log-level=1 --use-cras --enable-wayland-server --user-data-dir=/home/chronos --max-unused-resource-memory-usage-percentage=5 --login-profile=user --enable-natural-scroll-default --has-chromeos-keyboard --default-wallpaper-large=/usr/share/chromeos-assets/wallpaper/default_large.jpg --default-wallpaper-small=/usr/share/chromeos-assets/wallpaper/default_small.jpg --child-wallpaper-large=/usr/share/chromeos-assets/wallpaper/child_large.jpg --child-wallpaper-small=/usr/share/chromeos-assets/wallpaper/child_small.jpg --guest-wallpaper-large=/usr/share/chromeos-assets/wallpaper/guest_large.jpg --guest-wallpaper-small=/usr/share/chromeos-assets/wallpaper/guest_small.jpg --enable-prefixed-encrypted-media --enterprise-enrollment-initial-modulus=15 --enterprise-enrollment-modulus-limit=19 --vmodule=screen_locker=2,webui_screen_locker=2,lock_state_controller=2,webui_login_view=2,power_button_observer=2,*ui/display/chromeos*=1,*ash/display*=1,*ui/ozone*=1,*zygote*=1,*plugin*=2,*chromeos/login/*=1,power_manager_client=1,renderer_freezer=1,*arc/*=1 --login-user=bsittler@google.com --login-profile=c7e58117eeff57b61e77291f2e686c17c533902c --flag-switches-begin --allow-nacl-socket-api=* --enable-touchpad-three-finger-click --ash-debug-shortcuts --ash-enable-touch-view-testing --ash-md=experimental --enable-browser-task-scheduler --debug-packed-apps --enable-device-discovery-notifications --no-pings --enable-new-bookmark-apps --enable-add-to-shelf --enable-app-window-controls --enable-asm-wasm --enable-offer-upload-credit-cards --enable-canvas-2d-dynamic-rendering-mode-switching --enable-clear-browsing-data-counters --enable-datasaver-prompt --enable-devtools-experiments --enable-drive-search-in-app-launcher --enable-proximity-auth-bluetooth-low-energy-discovery --enable-proximity-auth-proximity-detection --enable-embedded-extension-options --enable-experimental-accessibility-features --enable-extension-action-redesign --enable-fast-unload --enable-files-details-panel --ash-enable-fullscreen-app-list --enable-google-branded-context-menu --enable-grouped-history --enable-icon-ntp --javascript-harmony --enable-md-policy-page --enable-nacl --enable-native-cups --enable-offer-store-unmasked-wallet-cards --enable-offline-auto-reload-visible-only --enable-offline-auto-reload --enable-password-generation --enable-permission-action-reporting --enable-permissions-blacklist --enable-print-preview-register-promos --enable-request-tablet-site --enable-settings-window --enable-single-click-autofill --enable-site-engagement-service --enable-suggestions-with-substring-match --enable-sync-app-list --enable-tab-audio-muting --enable-touch-drag-drop --enable-video-player-chromecast-support --enable-web-app-frame --enable-wasm --enable-webrtc-stun-origin --enable-wifi-credential-sync --enable-experimental-input-view-features --extension-content-verification=enforce --enable-files-quick-view --inert-visual-viewport --enable-lcd-text --mark-non-secure-as=non-secure --media-router=1 --memory-pressure-thresholds=conservative --enable-network-portal-notification --secondary-ui-md --show-saved-copy=primary --top-chrome-md=material-hybrid --enable-features=AutofillCreditCardSigninPromo,EmojiHandwritingVoiceInput,FeaturePolicy,MaterialDesignExtensions,MaterialDesignHistory,MaterialDesignSettings,OptInImeMenu,OriginTrials,QuickUnlockPin,SafeSearchUrlReporting,ScrollAnchoring,SpeculativeLaunchServiceWorker,StaleWhileRevalidate2,affiliation-based-matching,brotli-encoding,enable-manual-password-generation,enable-password-force-saving,fill-on-account-select,password-import-export,token-binding --disable-features=drop-sync-credential,enable-automatic-password-saving,protect-sync-credential,protect-sync-credential-on-reauth --flag-switches-end
Executable Path	/opt/google/chrome/chrome
Profile Path	/home/chronos/u-c7e58117eeff57b61e77291f2e686c17c533902c
Variations	6a89113b-2bdd0794
d0bd833b-85fb2903
16e0dd70-3f4a17df
90757ebb-870290a7
31101bd6-85fb2903
241fff6c-1122393
1e528f0f-15305a2
8739b412-4f7edc42
e197bfc9-ca7d8d80
8364a5c2-ca7d8d80
dbeef594-3d47f4f4
7c1bc906-ff96eb58
2a33b90e-65bced95
ba3f87da-5b060836
5ca89f9-ca7d8d80
76b48ab8-a2567007
31362330-ca7d8d80
f15c1c09-ca7d8d80
811bc6bc-d93a0620
9e201a2b-3f4a17df
9d315c2-9597b6c7
5274eb09-3f4a17df
a4566d9e-3d47f4f4
2e109477-bcf405c8
8f62251a-4757d2a7
6b121ae7-5e15bfb2
5139837c-f23d1dea
7f8176d9-3f4a17df
f79cb77b-1963db0f
23a898eb-e0e2610f
74df3f1-3f4a17df
7382e39a-3f4a17df
4ea303a6-ffbe6084
24cd6bf8-d8542277
7a3692af-b8c27ec3
f2e050c6-bc6856d9
fe9bec35-186f5907
9736de91-3f4a17df
dbffab5d-ca7d8d80
de03e059-843072a8
ca314179-9597b6c7
867c4c68-3f4a17df
b2f0086-b4530445
adda5502-3d47f4f4
3ac60855-3ec2a267
f296190c-8965af99
4442aae2-6e597ede
ed1d377-e1cc0f14
75f0f0a0-a5822863
e2b18481-4c073154
e7e71889-4ad60575
fe05be5f-4001c964
61b920c1-1410f10

Indeed, --ash-md=experimental is the culprit. Profiles with that set see the broken UI, others don't.

Components+labels are each a guess, feel free to improve on those guesses :)

Evan, is this a dupe of  Issue 653241 ?

Re #4, I'm almost certain that it is. This is fixed on ToT and should roll out in the next canary.