Settings WebUI: Fix accidental toggling of hardware acceleration setting.

settings-toggle-button, and cr-toggle need to be migrated from 'click' to 'tap'
at the same time, otherwise calling stopPropagation() has no effect.

Bug: 815173
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I847ca9892de3c108269995c10647ff16d935d8a5
Reviewed-on: https://chromium-review.googlesource.com/937904Reviewed-by: Hector Carmona <hcarmona@chromium.org>
Commit-Queue: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#539250}

chrome/browser/resources/settings/system_page/system_page.html

@@ -24,7 +24,7 @@
         label="$i18n{hardwareAccelerationLabel}">
       <template is="dom-if" if="[[shouldShowRestart_(
           prefs.hardware_acceleration_mode.enabled.value)]]">
-        <paper-button on-click="onRestartTap_" slot="more-actions">
+        <paper-button on-tap="onRestartTap_" slot="more-actions">
           $i18n{restart}
         </paper-button>
       </template>