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

tools/metrics/histograms/verify_enum_custom_flags_test_data/mock_histograms.xml

Index: tools/metrics/histograms/verify_enum_custom_flags_test_data/mock_histograms.xml
diff --git a/tools/metrics/histograms/verify_enum_custom_flags_test_data/mock_histograms.xml b/tools/metrics/histograms/verify_enum_custom_flags_test_data/mock_histograms.xml
new file mode 100644
index 0000000000000000000000000000000000000000..9730085f79bd337fc10dccab74a9267ef2426fec
--- /dev/null
+++ b/tools/metrics/histograms/verify_enum_custom_flags_test_data/mock_histograms.xml
@@ -0,0 +1,73 @@
+<!--
+Copyright 2013 The Chromium Authors. All rights reserved.
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file.
+-->
+
+<histogram-configuration>
+
+<!-- Histogram definitions -->
+
+<histograms>
+
+<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>
+
+</histograms>
+
+<!-- Enum types -->
+
+<enums>
+
+<enum name="LoginConsumerWhitelist" type="int">
+  <int value="0" label="ANY_USER_ALLOWED">Any user can sign in</int>
+  <int value="1" label="ONLY_WHITELISTED_ALLOWED">Whitelisted users only</int>
+</enum>
+
+<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="3937817818" label="allow-insecure-websocket-from-https-origin"/>
+  <int value="4053240068" label="allow-nacl-socket-api"/>
+  <int value="3199195749" label="apps-keep-chrome-alive"/>
+  <int value="464393358" label="ash-debug-shortcuts"/>
+  <int value="2167146710" label="ash-enable-touch-view-testing"/>
+  <int value="4002198259" label="ash-touch-hud"/>
+  <int value="2449122923" label="debug-packed-apps"/>
+  <int value="3702879077" label="default-tile-height"/>
+  <int value="2907027286" label="default-tile-width"/>
+  <int value="958598180" label="disable-accelerated-2d-canvas"/>
+  <int value="2432033880" label="disable-accelerated-fixed-root-background"/>
+  <int value="1275878421" label="disable-accelerated-overflow-scroll"/>
+  <int value="3552511345" label="disable-accelerated-video-decode"/>
+  <int value="3990756916" label="disable-account-consistency"/>
+  <int value="2184754039" label="disable-app-list-app-info"/>
+  <int value="1850282810" label="disable-app-list-voice-search"/>
+  <int value="548644674" label="disable-async-dns"/>
+  <int value="26833865" label="disable-boot-animation"/>
+  <int value="2704408632" label="disable-cast"/>
+  <int value="3565396945" label="disable-click-delay"/>
+  <int value="643197352" label="disable-compositor-touch-hit-testing"/>
+  <int value="4101571515" label="disable-contextual-search"/>
+  <int value="2232731446" label="disable-delegated-renderer"/>
+  <int value="2163827587" label="disable-device-discovery"/>
+  <int value="650058406" label="disable-device-discovery-notifications"/>
+  <int value="2068691566" label="disable-device-enumeration"/>
+  <int value="3957684781" label="disable-direct-write"/>
+  <int value="841992486" label="disable-display-color-calibration"/>
+  <int value="3078149563" label="disable-distance-field-text"/>
+  <int value="2614534539" label="disable-embedded-shared-worker"/>
+  <int value="1926620385" label="disable-fast-text-autosizing"/>
+  <int value="4260500459" label="disable-fixed-position-compositing"/>
+</enum>
+
+</enums>
+
+</histogram-configuration>