bluetooth: Add sidebar and page manager for chrome://bluetooth-internals.

ui/webui/resources/webui_resources.grd

 <?xml version="1.0" encoding="UTF-8"?>
 <!-- This comment is only here because changes to resources are not picked up
 without changes to the corresponding grd file. -->
 <grit latest_public_release="0" current_release="1" output_all_resource_defines="false">
   <outputs>
     <output filename="grit/webui_resources.h" type="rc_header">
       <emit emit_type='prepend'></emit>
     </output>
     <output filename="grit/webui_resources_map.cc"
             type="resource_file_map_source" />
@@ skipping 288 matching lines @@
       <structure name="IDR_WEBUI_HTML_CR_UI_FOCUS_ROW"
                  file="html/cr/ui/focus_row.html" type="chrome_html" />
       <structure name="IDR_WEBUI_HTML_CR_UI_MENU"
                  file="html/cr/ui/menu.html" type="chrome_html" />
       <structure name="IDR_WEBUI_HTML_CR_UI_MENU_BUTTON"
                  file="html/cr/ui/menu_button.html" type="chrome_html" />
       <structure name="IDR_WEBUI_HTML_CR_UI_MENU_ITEM"
                  file="html/cr/ui/menu_item.html" type="chrome_html" />
       <structure name="IDR_WEBUI_HTML_CR_UI_OVERLAY"
                  file="html/cr/ui/overlay.html" type="chrome_html" />
+      <structure name="IDR_WEBUI_HTML_CR_UI_PAGE_MANAGER_PAGE"
+                 file="html/cr/ui/page_manager/page.html" type="chrome_html"
+                 flattenhtml="true" />
+      <structure name="IDR_WEBUI_HTML_CR_UI_PAGE_MANAGER_PAGE_MANAGER"
+                 file="html/cr/ui/page_manager/page_manager.html"
+                 type="chrome_html" />
       <structure name="IDR_WEBUI_HTML_CR_UI_POSITION_UTIL"
                  file="html/cr/ui/position_util.html" type="chrome_html" />
       <structure name="IDR_WEBUI_HTML_EVENT_TRACKER"
                  file="html/event_tracker.html" type="chrome_html" />
       <structure name="IDR_WEBUI_HTML_ICON"
                  file="html/icon.html" type="chrome_html" />
       <structure name="IDR_WEBUI_HTML_I18N_TEMPLATE"
                  file="html/i18n_template.html" type="chrome_html" />
       <structure name="IDR_WEBUI_HTML_MD_SELECT_CSS_HTML"
                  file="html/md_select_css.html" type="chrome_html"
@@ skipping 154 matching lines @@
                    file="js/chromeos/ui_account_tweaks.js"
                    type="chrome_html" />
       </if>
       <if expr="not is_android">
         <part file="cr_elements_resources.grdp" />
         <part file="polymer_resources.grdp" />
       </if>
     </structures>
   </release>
 </grit>