Make switch access settings button behave properly

Also modify it to look like buttons for ChromeVox / Select to Speak

Bug: 842242
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I1dfa42917ac35d13f300090e92672f8f62e3d798
Reviewed-on: https://chromium-review.googlesource.com/1055770
Commit-Queue: Zach Helfinstein <zhelfins@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#560860}

chrome/browser/resources/chromeos/switch_access/manifest.json.jinja2

@@ -29,5 +29,6 @@
   ],
   "automation": {
     "desktop": true
-  }
+  },
+  "options_page": "options.html"
 }

chrome/browser/resources/settings/a11y_page/manage_a11y_page.html

@@ -179,13 +179,16 @@
       <settings-toggle-button
           pref="{{prefs.settings.a11y.switch_access}}"
           label="$i18n{switchAccessLabel}">
-        <paper-icon-button-light slot="more-actions" class="icon-settings"
-            hidden="[[!prefs.settings.a11y.switch_access.value]]">
-          <button on-click="onSwitchAccessSettingsTap_"
-              aria-label="$i18n{selectToSpeakOptionsLabel}">
-          </button>
-        </paper-icon-button-light>
       </settings-toggle-button>
+      <iron-collapse opened="[[prefs.settings.a11y.switch_access.value]]">
+        <div class="settings-box" actionable
+            on-click="onSwitchAccessSettingsTap_">
+          <div class="start">$i18n{switchAccessOptionsLabel}</div>
+          <paper-icon-button-light class="icon-external">
+            <button aria-label="$i18n{switchAccessOptionsLabel}"></button>
+          </paper-icon-button-light>
+        </div>
+      </iron-collapse>
     </template>
     <div class="settings-box two-line" on-click="onKeyboardTap_" actionable>
       <div class="start">