MD Settings: Add action indicators in About page buttons.

chrome/browser/resources/settings/about_page/about_page.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="/about_page/about_page_browser_proxy.html">
 <link rel="import" href="/i18n_setup.html">
 <link rel="import" href="/icons.html">
 <link rel="import" href="/lifetime_browser_proxy.html">
 <link rel="import" href="/route.html">
 <link rel="import" href="/settings_page/main_page_behavior.html">
 <link rel="import" href="/settings_page/settings_animated_pages.html">
 <link rel="import" href="/settings_page/settings_section.html">
 <link rel="import" href="/settings_page_css.html">
@@ skipping 123 matching lines @@
                 <paper-button id="checkForUpdates" class="secondary-button"
                     hidden="[[!shouldShowCheckUpdates_(
                         currentUpdateStatusEvent_)]]"
                     on-tap="onCheckUpdatesTap_">
                   $i18n{aboutCheckForUpdates}
                 </paper-button>
 </if>
               </span>
             </div>
             <div id="help" class="settings-box" on-tap="onHelpTap_" actionable>
-              $i18n{aboutGetHelpUsingChrome}
+              <div class="start">$i18n{aboutGetHelpUsingChrome}</div>
+              <button class="icon-external" is="paper-icon-button-light">
+              </button>
             </div>
 <if expr="_google_chrome">
             <div id="reportIssue" class="settings-box" actionable
                 on-tap="onReportIssueTap_">
-              $i18n{aboutReportAnIssue}
+              <div class="start">$i18n{aboutReportAnIssue}</div>
+              <button class="subpage-arrow" is="paper-icon-button-light">
+              </button>
             </div>
 </if>
 <if expr="chromeos">
             <div class="settings-box" on-tap="onDetailedBuildInfoTap_"
                 actionable>
-              $i18n{aboutDetailedBuildInfo}
+              <div class="start">$i18n{aboutDetailedBuildInfo}</div>
+              <button class="subpage-arrow" is="paper-icon-button-light">
+              </button>
             </div>
 </if>
             <div class="settings-box product-info copyable">
               <div class="info-section">
                 <div class="secondary">$i18n{aboutProductTitle}</div>
                 <div class="secondary">$i18n{aboutProductCopyright}</div>
               </div>
 
               <div class="info-section">
                 <div class="secondary">$i18nRaw{aboutProductLicense}</div>
@@ skipping 18 matching lines @@
               <settings-detailed-build-info></settings-detailed-build-info>
             </settings-subpage>
           </template>
 </if>
         </settings-animated-pages>
       </settings-section>
     </div>
   </template>
   <script src="about_page.js"></script>
 </dom-module>