Collect UMA statistics on which chrome://flags lead to chrome restart on ChromeOS.

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index bba0069b55ea8d66ca9883825aac51903da77ba4..58fccdfcacd2d391b93d3e68d27978e07e83bb39 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -9518,6 +9518,14 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Login.CustomFlags" enum="LoginCustomFlags">
+  <owner>alemate@chromium.org</owner>
+  <summary>
+    A set of chrome flags that required browser restart on Chrome OS user sign
+    in.
+  </summary>
+</histogram>
+
 <histogram name="Login.FailureReason" enum="LoginFailureReason">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <summary>Chrome OS login failure reason.</summary>
@@ -39272,6 +39280,260 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="1" label="ONLY_WHITELISTED_ALLOWED">Whitelisted users only</int>
 </enum>
 
+<!--
+Values in LoginCustomFlags are:  value=CRC32(label).
+This enum is verified by AboutFlagsHistogramTest unit test.
+To add new entry, add if with any value and run test to compute valid value.
+-->
+
+<enum name="LoginCustomFlags" type="int">
+  <summary>Chrome flags that lead to chrome restart on ChromeOS.</summary>
+  <int value="0" label="BAD_FLAG_FORMAT">
+    Command-line flag doesn't start with two dashes.
+  </int>
+  <int value="1003861" label="disable-saml-signin"/>
+  <int value="26833865" label="disable-boot-animation"/>
+  <int value="71094525" label="enable-threaded-compositing"/>
+  <int value="98593350" label="disable-quic-https"/>
+  <int value="104836252" label="disable-gpu-rasterization"/>
+  <int value="118817878" label="fast-user-switching"/>
+  <int value="128856526" label="reset-app-list-install-state"/>
+  <int value="147580374" label="enable-easy-unlock"/>
+  <int value="245658014" label="enable-apps-show-on-first-paint"/>
+  <int value="247000221" label="enable-settings-window"/>
+  <int value="268768021" label="enhanced-bookmarks-experiment"/>
+  <int value="307643299" label="disable-virtual-keyboard-overscroll"/>
+  <int value="315720707" label="disable-search-button-in-omnibox"/>
+  <int value="327062143" label="disable-transition-compositing"/>
+  <int value="345521529" label="enable-origin-chip-on-srp"/>
+  <int value="403779575" label="ssl-interstitial-v2-colorful"/>
+  <int value="429787273" label="disable-password-manager-reauthentication"/>
+  <int value="437730474" label="enable-syncfs-directory-operation"/>
+  <int value="440685536" label="enable-async-dns"/>
+  <int value="464393358" label="ash-debug-shortcuts"/>
+  <int value="496241031" label="enable-service-worker"/>
+  <int value="499546388" label="force-device-scale-factor"/>
+  <int value="503514397" label="tab-capture-upscale-quality"/>
+  <int value="548644674" label="disable-async-dns"/>
+  <int value="563523290" label="save-page-as-mhtml"/>
+  <int value="585381753" label="disable-quickoffice-component-app"/>
+  <int value="620309101" label="enable-fast-text-autosizing"/>
+  <int value="622070030" label="enable-spdy4"/>
+  <int value="630297204" label="disable-pinch-virtual-viewport"/>
+  <int value="643197352" label="disable-compositor-touch-hit-testing"/>
+  <int value="650058406" label="disable-device-discovery-notifications"/>
+  <int value="663012457" label="enable-first-run-ui-transitions"/>
+  <int value="668609690" label="disable-lcd-text"/>
+  <int value="678591118" label="enable-distance-field-text"/>
+  <int value="688456340" label="disable-new-profile-management"/>
+  <int value="717788471" label="nacl-debug-mask"/>
+  <int value="725391525" label="enable-accelerated-fixed-root-background"/>
+  <int value="731679855" label="malware-interstitial-v2"/>
+  <int value="765241631" label="enable-ephemeral-apps"/>
+  <int value="777048661" label="disable-ntp-other-sessions-menu"/>
+  <int value="777318388" label="file-manager-enable-new-gallery"/>
+  <int value="793827406" label="enable-nacl-debug"/>
+  <int value="795105205" label="enable-panels"/>
+  <int value="802637372" label="manual-enhanced-bookmarks-optout"/>
+  <int value="802793005" label="enable-accessibility-tab-switcher"/>
+  <int value="811554672" label="enable-delegated-renderer"/>
+  <int value="818208367" label="scroll-end-effect"/>
+  <int value="837185577" label="enable-zero-suggest-most-visited"/>
+  <int value="841846152" label="enable-search-button-in-omnibox-always"/>
+  <int value="841992486" label="disable-display-color-calibration"/>
+  <int value="856276782" label="disable-views-rect-based-targeting"/>
+  <int value="861731285" label="disable-offline-auto-reload-visible-only"/>
+  <int value="889591193" label="enable-carrier-switching"/>
+  <int value="905746312" label="disable-webrtc-hw-decoding"/>
+  <int value="919424244" label="new-avatar-menu"/>
+  <int value="927656248" label="enable-one-copy"/>
+  <int value="941080531" label="disable-touch-adjustment"/>
+  <int value="942720653" label="enable-network-portal-notification"/>
+  <int value="958598180" label="disable-accelerated-2d-canvas"/>
+  <int value="990329408" label="disable-offline-load-stale-cache"/>
+  <int value="1023565686" label="enable-quic-https"/>
+  <int value="1054604307" label="disable-suggestions-service"/>
+  <int value="1073932118" label="do-not-ignore-autocomplete-off"/>
+  <int value="1081135990" label="enable-fixed-position-compositing"/>
+  <int value="1087074171" label="ssl-interstitial-v1"/>
+  <int value="1126971813" label="disable-touch-editing"/>
+  <int value="1147109479" label="enable-device-discovery-notifications"/>
+  <int value="1148750716" label="touch-scrolling-mode"/>
+  <int value="1162171476" label="disable-permissions-bubbles"/>
+  <int value="1171292682" label="enable-encrypted-media"/>
+  <int value="1185953440" label="enable-overlay-scrollbar"/>
+  <int value="1195364470" label="enable-web-based-signin"/>
+  <int value="1212229923" label="disable-webrtc"/>
+  <int value="1217402371"
+      label="enable-search-button-in-omnibox-for-str-or-iip"/>
+  <int value="1226871309" label="enable-password-generation"/>
+  <int value="1245838705" label="disable-pinch"/>
+  <int value="1274995237" label="enable-download-resumption"/>
+  <int value="1275878421" label="disable-accelerated-overflow-scroll"/>
+  <int value="1296801953" label="disable-input-view"/>
+  <int value="1302578131" label="performance-monitor-gathering"/>
+  <int value="1313047846" label="disable-webaudio"/>
+  <int value="1330170923" label="enable-app-list"/>
+  <int value="1346037021" label="prefetch-search-results"/>
+  <int value="1348299604" label="enable-web-midi"/>
+  <int value="1355498862" label="enable-app-install-alerts"/>
+  <int value="1370396266" label="silent-debugger-extension-api"/>
+  <int value="1371315556" label="enable-smooth-scrolling"/>
+  <int value="1376788081" label="disable-threaded-compositing"/>
+  <int value="1385787929" label="show-composited-layer-borders"/>
+  <int value="1393218842" label="max-tiles-for-interest-area"/>
+  <int value="1411449621" label="enable-webgl-draft-extensions"/>
+  <int value="1412954715" label="disable-sync-app-list"/>
+  <int value="1497443263" label="disable-offline-auto-reload"/>
+  <int value="1525261285" label="enable-embeddedsearch-api"/>
+  <int value="1550903461" label="enable-spdy-proxy-dev-auth-origin"/>
+  <int value="1553710329" label="malware-interstitial-v3"/>
+  <int value="1562216735" label="enable-session-crashed-bubble"/>
+  <int value="1570279123" label="ssl-interstitial-v2-gray"/>
+  <int value="1589452936" label="ignore-gpu-blacklist"/>
+  <int value="1596334481" label="enable-spelling-feedback-field-trial"/>
+  <int value="1702838523" label="enable-lcd-text"/>
+  <int value="1707365356" label="enable-linkable-ephemeral-apps"/>
+  <int value="1708786007" label="enable-centered-app-list"/>
+  <int value="1730412122" label="enable-app-window-controls"/>
+  <int value="1740698312" label="enable-touch-drag-drop"/>
+  <int value="1772630041" label="enable-apps-file-associations"/>
+  <int value="1779548114" label="enable-prominent-url-app-flow"/>
+  <int value="1795617820" label="extension-content-verification"/>
+  <int value="1813294601" label="enable-cloud-devices"/>
+  <int value="1849706996" label="enable-instant-search-clicks"/>
+  <int value="1850282810" label="disable-app-list-voice-search"/>
+  <int value="1864791046" label="enable-contextual-search"/>
+  <int value="1894047852" label="enable-virtual-keyboard"/>
+  <int value="1926541569" label="enable-account-consistency"/>
+  <int value="1926620385" label="disable-fast-text-autosizing"/>
+  <int value="1928092730" label="enable-high-dpi-fixed-position-compositing"/>
+  <int value="1945365404" label="disable-quic"/>
+  <int value="1963609039" label="enable-zero-suggest-ether-serp"/>
+  <int value="1966989877" label="enable-text-input-focus-manager"/>
+  <int value="1974048145" label="enable-input-view"/>
+  <int value="1992335749" label="enable-experimental-app-list"/>
+  <int value="2009473987" label="enable-print-preview-register-promos"/>
+  <int value="2015959197" label="enable-gesture-tap-highlight"/>
+  <int value="2022319246" label="no-pings"/>
+  <int value="2040434001"
+      label="disable-minimize-on-second-launcher-item-click"/>
+  <int value="2068691566" label="disable-device-enumeration"/>
+  <int value="2093075173" label="file-manager-enable-new-audio-player"/>
+  <int value="2121796119"
+      label="disable-gesture-requirement-for-media-playback"/>
+  <int value="2124218647" label="enable-impl-side-painting"/>
+  <int value="2153289625" label="force-gpu-rasterization"/>
+  <int value="2163827587" label="disable-device-discovery"/>
+  <int value="2167146710" label="ash-enable-touch-view-testing"/>
+  <int value="2179676522" label="disable-layer-squashing"/>
+  <int value="2184689563" label="show-autofill-type-predictions"/>
+  <int value="2184754039" label="disable-app-list-app-info"/>
+  <int value="2198919449" label="enable-devtools-experiments"/>
+  <int value="2207567625" label="tab-capture-downscale-quality"/>
+  <int value="2232731446" label="disable-delegated-renderer"/>
+  <int value="2282936846" label="enable-bleeding-edge-rendering-fast-paths"/>
+  <int value="2308549929" label="enable-viewport-meta"/>
+  <int value="2309253622" label="enable-service-worker-sync"/>
+  <int value="2339544559" label="enable-touch-editing"/>
+  <int value="2400171980" label="enable-translate-new-ux"/>
+  <int value="2409368035" label="js-flags"/>
+  <int value="2428457975" label="enable-quic"/>
+  <int value="2428635417" label="enable-pinch"/>
+  <int value="2430875311" label="mediadrm-enable-non-compositing"/>
+  <int value="2432033880" label="disable-accelerated-fixed-root-background"/>
+  <int value="2449122923" label="debug-packed-apps"/>
+  <int value="2464112354" label="manual-enhanced-bookmarks"/>
+  <int value="2494904122" label="enable-tcp-fastopen"/>
+  <int value="2512199616" label="enable-origin-chip-always"/>
+  <int value="2543840966" label="enable-search-button-in-omnibox-for-str"/>
+  <int value="2613685268" label="enable-harfbuzz-rendertext"/>
+  <int value="2614534539" label="disable-embedded-shared-worker"/>
+  <int value="2622828186" label="enable-virtual-keyboard-overscroll"/>
+  <int value="2624151057" label="enable-sync-app-list"/>
+  <int value="2624715608" label="disable-gesture-tap-highlight"/>
+  <int value="2640370465" label="enable-gpu-rasterization"/>
+  <int value="2704408632" label="disable-cast"/>
+  <int value="2714850086" label="enable-suggestions-service"/>
+  <int value="2740537123" label="disable-zero-suggest"/>
+  <int value="2770008092" label="touch-events"/>
+  <int value="2829445397" label="enable-fast-unload"/>
+  <int value="2856796654" label="enable-scripts-require-action"/>
+  <int value="2859814177" label="enable-automatic-password-saving"/>
+  <int value="2861121187" label="disable-media-source"/>
+  <int value="2866390389" label="disable-save-password-bubble"/>
+  <int value="2896529261" label="enable-experimental-extension-apis"/>
+  <int value="2907027286" label="default-tile-width"/>
+  <int value="3035734751" label="enable-streamlined-hosted-apps"/>
+  <int value="3049866429" label="show-fps-counter"/>
+  <int value="3056839604" label="disable-network-portal-notification"/>
+  <int value="3069700035" label="disable-session-crashed-bubble"/>
+  <int value="3078149563" label="disable-distance-field-text"/>
+  <int value="3139649325" label="overscroll-history-navigation"/>
+  <int value="3143833800" label="disable-origin-chip"/>
+  <int value="3155845256" label="enable-experimental-input-view-features"/>
+  <int value="3162511334" label="enable-offline-load-stale-cache"/>
+  <int value="3169712872" label="disable-touch-drag-drop"/>
+  <int value="3199195749" label="apps-keep-chrome-alive"/>
+  <int value="3230178885" label="enable-sync-synced-notifications"/>
+  <int value="3255775532" label="enable-accelerated-overflow-scroll"/>
+  <int value="3326837898" label="enable-offline-auto-reload"/>
+  <int value="3419836753" label="disable-impl-side-painting"/>
+  <int value="3434230092" label="enable-cloud-print-xps"/>
+  <int value="3444708982" label="enable-touchpad-three-finger-click"/>
+  <int value="3464232104" label="enable-pinch-virtual-viewport"/>
+  <int value="3506482634" label="enable-experimental-canvas-features"/>
+  <int value="3520091863" label="enable-experimental-web-platform-features"/>
+  <int value="3552511345" label="disable-accelerated-video-decode"/>
+  <int value="3565396945" label="disable-click-delay"/>
+  <int value="3583370429" label="disable-settings-window"/>
+  <int value="3593092408" label="disable-password-generation"/>
+  <int value="3635177120" label="disable-webgl"/>
+  <int value="3646960667" label="disable-zero-copy"/>
+  <int value="3654603626" label="enable-avfoundation"/>
+  <int value="3662674785" label="enable-permissions-bubbles"/>
+  <int value="3685172972" label="disable-pnacl"/>
+  <int value="3702879077" label="default-tile-height"/>
+  <int value="3705531990" label="enable-request-tablet-site"/>
+  <int value="3723444509" label="disable-overlay-scrollbar"/>
+  <int value="3739712378" label="enable-scroll-prediction"/>
+  <int value="3790743608" label="disable-spdy-proxy-dev-auth-origin"/>
+  <int value="3818373305" label="enable-zero-copy"/>
+  <int value="3853535426" label="google-profile-info"/>
+  <int value="3883226003" label="enable-answers-in-suggest"/>
+  <int value="3921341065" label="enable-nacl"/>
+  <int value="3923619430" label="enable-simplified-fullscreen"/>
+  <int value="3937817818" label="allow-insecure-websocket-from-https-origin"/>
+  <int value="3938901992" label="enable-new-ntp"/>
+  <int value="3953012705" label="wallet-service-use-sandbox"/>
+  <int value="3957684781" label="disable-direct-write"/>
+  <int value="3990756916" label="disable-account-consistency"/>
+  <int value="4002198259" label="ash-touch-hud"/>
+  <int value="4030070834" label="enable-deferred-image-decoding"/>
+  <int value="4045821194" label="disable-prefixed-encrypted-media"/>
+  <int value="4049994530" label="num-raster-threads"/>
+  <int value="4050061152" label="enable-offline-auto-reload-visible-only"/>
+  <int value="4052327683" label="enable-filemanager-mtp"/>
+  <int value="4053240068" label="allow-nacl-socket-api"/>
+  <int value="4054415941" label="enable-zero-suggest-personalized"/>
+  <int value="4072329107" label="disable-text-input-focus-manager"/>
+  <int value="4083928056" label="out-of-process-pdf"/>
+  <int value="4084952204" label="disable-software-rasterizer"/>
+  <int value="4101571515" label="disable-contextual-search"/>
+  <int value="4128264510" label="enable-zero-suggest-ether-noserp"/>
+  <int value="4129203689" label="extensions-on-chrome-urls"/>
+  <int value="4152950634" label="use-simple-cache-backend"/>
+  <int value="4168632606" label="enable-spelling-auto-correct"/>
+  <int value="4170513571" label="enable-transition-compositing"/>
+  <int value="4175668646" label="enable-swipe-selection"/>
+  <int value="4216439788" label="disable-webrtc-hw-encoding"/>
+  <int value="4243942393" label="enable-save-password-bubble"/>
+  <int value="4246277765" label="new-profile-management"/>
+  <int value="4247966401" label="disable-new-ntp"/>
+  <int value="4260500459" label="disable-fixed-position-compositing"/>
+  <int value="4290387893" label="disable-sync-synced-notifications"/>
+</enum>
+
 <enum name="LoginFailureReason" type="int">
   <int value="0" label="NONE">None</int>
   <int value="1" label="COULD_NOT_MOUNT_CRYPTOHOME">