Replace mic key with search in a11y keyboard.

ui/keyboard/resources/layouts/system-qwerty.html

 <!--
   -- 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.
   -->
 
 <link id="spacebar-row" rel="import" href="spacebar-row.html">
 <link id="function-key-row" rel="import" href="function-key-row.html">
 
 <template>
   <kb-keyset id="system-qwerty-upper">
     <kb-row>
       <kb-key-import importId="function-key-row"></kb-key-import>
     </kb-row>
     <kb-row>
       <kb-key-sequence invert=true keys="'1234567890-="
           hintTexts="~!@#$%^&*()_+"> </kb-key-sequence>
       <kb-key class="dark" char="&#x0008;" repeat align="right"
           weight="160">backspace</kb-key>
     </kb-row>
     <kb-row>
       <kb-key class="dark" char="&#x0009;" align="left"
           weight="160">tab</kb-key>
       <kb-key-sequence keys="QWERTYUIOP"></kb-key-sequence>
       <kb-key-sequence invert=true keys="[]\"
           hintTexts="{}|"></kb-key-sequence>
     </kb-row>
     <kb-row>
-      <kb-key class="microphone dark" char="Microphone" weight="150"></kb-key>
+      <kb-key class="search dark" char="Search" image='search' weight="150">

[bshe, 2014/01/29 20:28:00]

do you need to add a special case in kb-keyboard to prevent "Search" being
typed?

+      </kb-key>
       <kb-key-sequence keys="ASDFGHJKL"></kb-key-sequence>
       <kb-key-sequence invert=true keys=";&apos;" hintTexts=':"'>
       </kb-key-sequence>
       <kb-key class="dark" char="&#x000A;" align="right"
           weight="210">enter</kb-key>
     </kb-row>
     <kb-row>
       <kb-shift-key weight="230" align="left">shift</kb-shift-key>
       <kb-key-sequence keys="ZXCVBNM"></kb-key-sequence>
       <kb-key-sequence invert=true keys=",./" hintTexts="<>?">
@@ skipping 30 matching lines @@
       <kb-key class="dark" weight="160" char="&#x0008;"
           repeat align="right">backspace</kb-key>
     </kb-row>
     <kb-row>
       <kb-key class="dark" char="&#x0009;" align="left"
           weight="160">tab</kb-key>
       <kb-key-sequence keys="qwertyuiop"></kb-key-sequence>
       <kb-key-sequence keys="[]\" hintTexts="{}|"></kb-key-sequence>
     </kb-row>
     <kb-row>
-      <kb-key class="microphone dark" char="Microphone" weight="150"></kb-key>
+      <kb-key class="search dark" char="Search" image='search' weight="150">
+      </kb-key>
       <kb-key-sequence keys="asdfghjkl"></kb-key-sequence>
       <kb-key-sequence keys=";&apos;" hintTexts=':"'></kb-key-sequence>
       <kb-key class="dark" char="&#x000A;" align="right"
           weight="210">enter</kb-key>
     </kb-row>
     <kb-row>
       <kb-shift-key weight="230" align="left">shift</kb-shift-key>
       <kb-key-sequence keys="zxcvbnm"></kb-key-sequence>
       <kb-key-sequence keys=",./" hintTexts="<>?"></kb-key-sequence>
       <kb-shift-key weight="230" align="right">shift</kb-shift-key>
@@ skipping 11 matching lines @@
       <kb-key class="dark" repeat char="Arrow-Down" image="down"
           weight="75"> </kb-key>
       <kb-key class="dark" repeat char="Arrow-Right" image="right"
           weight="75"></kb-key>
       <kb-hide-keyboard-key></kb-hide-keyboard-key>
     </kb-row>
     <kb-altkey-container hidden>
     </kb-altkey-container>
   </kb-keyset>
 </template>