Android: use grit target platform instead of define.

chrome/app/bookmarks_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Bookmarks specific strings (included from generated_resources.grd). -->
 <grit-part>
-  <if expr="not pp_ifdef('android') and not pp_ifdef('ios') and pp_ifdef('use_titlecase')">
+  <if expr="not is_android and not pp_ifdef('ios') and pp_ifdef('use_titlecase')">
     <message name="IDS_BOOKMARK_BAR_FOLDER_NAME" desc="In Title Case: Name shown in the tree for the Bookmarks Bar folder.">
       Bookmarks Bar
     </message>
   </if>
-  <if expr="not pp_ifdef('android') and not pp_ifdef('ios') and not pp_ifdef('use_titlecase')">
+  <if expr="not is_android and not pp_ifdef('ios') and not pp_ifdef('use_titlecase')">
     <message name="IDS_BOOKMARK_BAR_FOLDER_NAME" desc="Name shown in the tree for the Bookmarks Bar folder.">
       Bookmarks bar
     </message>
   </if>
 
   <!-- Begin of Bookmarks Bar strings-->
 
   <!-- The following two strings are shown when the user has no bookmarks yet. -->
   <message name="IDS_BOOKMARKS_NO_ITEMS" desc="Text shown when the user has no bookmarks">
     For quick access, place your bookmarks here on the bookmarks bar.
@@ skipping 34 matching lines @@
     <message name="IDS_BOOKMARK_BAR_MOBILE_FOLDER_NAME" desc="In Title Case: Name shown in the tree for the mobile bookmarks folder">
       Mobile Bookmarks
     </message>
     <message name="IDS_BOOKMARK_BAR_OTHER_FOLDER_NAME" desc="In Title Case: Name shown in the tree for the other bookmarks folder">
       Other Bookmarks
     </message>
     <message name="IDS_BOOKMARK_BAR_SHOW_APPS_SHORTCUT" desc="In Title Case: Name shown in the context menu to hide/show the apps shortcut in the bookmakr bar">
       Show Apps Shortcut
     </message>
   </if>
-  <if expr="pp_ifdef('android')">
+  <if expr="is_android">
     <message name="IDS_BOOKMARK_BAR_FOLDER_NAME" desc="Mobile: Name shown in the tree for the desktop bookmarks folder">
       Desktop bookmarks
     </message>
   </if>
   <if expr="pp_ifdef('ios')">
     <message name="IDS_BOOKMARK_BAR_FOLDER_NAME" desc="Mobile: Name shown in the tree for the desktop bookmarks folder">
       Desktop Bookmarks
     </message>
   </if>
   <message name="IDS_BOOKMARK_BAR_APPS_SHORTCUT_NAME" desc="Name shown in the bookmark bar for the apps page shortcut">
@@ skipping 297 matching lines @@
 
   <!-- Being of Bookmark Star button strings. -->
   <message name="IDS_TOOLTIP_STAR" desc="The tooltip shown when you hover the star button in the right side of the location bar.">
     Bookmark this page
   </message>
   <message name="IDS_TOOLTIP_STARRED" desc="The tooltip shown when you hover the star button in the right side of the location bar and the current page is bookmarked.">
     Edit bookmark for this page
   </message>
   <!-- End of Bookmark Star button strings. -->
 
-  <if expr="pp_ifdef('android')">
+  <if expr="is_android">
     <message name="IDS_BOOKMARK_EDIT_FOLDER" desc="Context menu item for editing a bookmark folder">
       Edit folder
     </message>
     <message name="IDS_BOOKMARK_REMOVE_FOLDER" desc="Context menu item for removing a bookmark folder">
       Remove folder
     </message>
   </if>
 
 </grit-part>