Refactors profile avatar selector into a Polymer element to use in md-settings & md-user-manager

chrome/app/settings_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Settings-specific strings (included from generated_resources.grd). -->
 <grit-part>
   <!-- About Page -->
   <if expr="chromeos">
     <message name="IDS_SETTINGS_ABOUT_PAGE_CHECK_FOR_UPDATES" desc="The button label to check for updates and apply (download and install) if found">
       Check for updates
     </message>
     <message name="IDS_SETTINGS_ABOUT_PAGE_CURRENT_CHANNEL_STABLE" desc="The stable label in the message about current channel.">
       stable
@@ skipping 1109 matching lines @@
   <!-- Sync / People Page -->
   <message name="IDS_SETTINGS_PEOPLE" desc="Name of the settings page which manages Chrome's signed-in Google profile.">
     People
   </message>
   <message name="IDS_SETTINGS_PEOPLE_MANAGE_OTHER_PEOPLE" desc="Label for the button that opens the multi-profile user manager.">
     Manage other people
   </message>
   <message name="IDS_SETTINGS_PEOPLE_MANAGE_SUPERVISED_USERS" desc="Label for the button that opens the supervised users dashboard.">
     Manage supervised users
   </message>
+  <message name="IDS_SETTINGS_CHANGE_PICTURE_PROFILE_PHOTO" desc="The text on the Google profile photo of the user.">
+    Google Profile photo
+  </message>
 
   <if expr="chromeos">
     <message name="IDS_SETTINGS_PEOPLE_ENABLE_SCREENLOCK" desc="The text on the checkbox to enable screenlocker for current user.">
       Require password to wake from sleep
     </message>
     <message name="IDS_SETTINGS_CHANGE_PICTURE_DIALOG_TITLE" desc="Title of the subpage shown when user wants to change his/her picture.">
       Change picture
     </message>
     <message name="IDS_SETTINGS_CHANGE_PICTURE_DIALOG_TEXT" desc="Text with description of what to do on Change picture subpage.">
       Choose a picture to display for your account on the sign-in screen.
@@ skipping 24 matching lines @@
     </message>
     <message name="IDS_SETTINGS_PHOTO_FLIPBACK_ACCESSIBLE_TEXT" desc="The accessible message to speak to announce horizontal back-flip of camera image to not-flipped state.">
       Photo flipped back
     </message>
     <message name="IDS_SETTINGS_CHANGE_PICTURE_PREVIEW_ALT" desc="Alt text for the big preview of user image.">
       User image preview
     </message>
     <message name="IDS_SETTINGS_CHANGE_PICTURE_AUTHOR_TEXT" desc="Author label.">
       Photo by
     </message>
-    <message name="IDS_SETTINGS_CHANGE_PICTURE_PROFILE_PHOTO" desc="The text on the Google profile photo of the user.">
-      Google Profile photo
-    </message>
     <message name="IDS_SETTINGS_CHANGE_PICTURE_PROFILE_LOADING_PHOTO" desc="The text on the loading stub for Google profile image.">
       Google Profile photo (loading)
     </message>
     <message name="IDS_SETTINGS_CHANGE_PICTURE_OLD_PHOTO" desc="The text on the existing photo from camera or file.">
       Existing photo from camera or file
     </message>
   </if>
 
   <if expr="not chromeos">
     <message name="IDS_SETTINGS_EDIT_PERSON" desc="Title of the edit person subpage">
@@ skipping 350 matching lines @@
       System
     </message>
     <message name="IDS_SETTINGS_SYSTEM_HARDWARE_ACCELERATION_LABEL" desc="Label for the checkbox that forces Chrome to render via hardware acceleration (GPU) when available.">
       Use hardware acceleration when available
     </message>
     <message name="IDS_SETTINGS_SYSTEM_PROXY_SETTINGS_BUTTON" desc="Text for the button that changes a user's network proxy settings.">
       Change proxy settings
     </message>
   </if>
 </grit-part>