About page UI: add confirmation message for release channel switch.

chrome/browser/resources/help/help.html

Index: chrome/browser/resources/help/help.html
diff --git a/chrome/browser/resources/help/help.html b/chrome/browser/resources/help/help.html
index 61f2be13bb47a7123189c5d336000902fa502570..a55a77320e6e926edfbdc0bb44505800344589f4 100644
--- a/chrome/browser/resources/help/help.html
+++ b/chrome/browser/resources/help/help.html
@@ -37,6 +37,21 @@
       <div>
         <span i18n-content="firmware"></span>&nbsp;<span id="firmware"></span>
       </div>
+</if>
+<if expr="pp_ifdef('chromeos') or pp_ifdef('_google_chrome') or is_linux">
+      <div id="update-status-container" hidden>
+        <div id="update-status-icon" class="up-to-date"></div>
+        <span id="update-status" i18n-content="updateCheckStarted"></span>
+      </div>
+      <div id="update-buttons-container">
+        <div id="update-percentage" hidden></div>
+<if expr="is_macosx">
+        <button id="promote" i18n-content="promote" hidden></button>
+</if>
+        <button id="relaunch" i18n-content="relaunch" hidden></button>
+      </div>
+</if>
+<if expr="pp_ifdef('chromeos')">
       <div id="more-info-container">
         <section id="channel-changer-container">
           <h3 i18n-content="channel"></h3>
@@ -45,6 +60,7 @@
             <option value="beta-channel" i18n-content="beta"></option>
             <option value="dev-channel" i18n-content="dev"></option>
           </select>
+          <div id="channel-change-confirmation" hidden></div>
         </section>
         <section>
           <h3 i18n-content="webkit"></h3>
@@ -71,19 +87,6 @@
           i18n-content="showMoreInfo">
       </button>
 </if>
-<if expr="pp_ifdef('chromeos') or pp_ifdef('_google_chrome') or is_linux">
-      <div id="update-status-container" hidden>
-        <div id="update-status-icon" class="up-to-date"></div>
-        <span id="update-status" i18n-content="updateCheckStarted"></span>
-      </div>
-      <div id="update-buttons-container">
-        <div id="update-percentage" hidden></div>
-<if expr="is_macosx">
-        <button id="promote" i18n-content="promote" hidden></button>
-</if>
-        <button id="relaunch" i18n-content="relaunch" hidden></button>
-      </div>
-</if>
     </div>
     <div id="product-container">
       <div i18n-content="productName"></div>