Support immersive fullscreen for non-video element

chrome/android/java/strings/android_chrome_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 <grit current_release="1" latest_public_release="0">
   <outputs>
     <output filename="values-am/android_chrome_strings.xml" lang="am" type="android" />
     <output filename="values-ar/android_chrome_strings.xml" lang="ar" type="android" />
     <output filename="values-bg/android_chrome_strings.xml" lang="bg" type="android" />
     <output filename="values-ca/android_chrome_strings.xml" lang="ca" type="android" />
     <output filename="values-cs/android_chrome_strings.xml" lang="cs" type="android" />
     <output filename="values-da/android_chrome_strings.xml" lang="da" type="android" />
     <output filename="values-de/android_chrome_strings.xml" lang="de" type="android" />
@@ skipping 1279 matching lines @@
       </message>
 
       <!-- Sad tab page -->
       <message name="IDS_SAD_TAB_SUGGESTIONS" desc="The help message displayed on the sad tab page after a tab crashes.">
         If you're seeing this frequently, try these <ph name="BEGIN_LINK">&lt;link&gt;</ph>suggestions<ph name="END_LINK">&lt;/link&gt;</ph>.
       </message>
 
       <!-- Fullscreen -->
       <message name="IDS_FULLSCREEN_API_NOTIFICATION" desc="Notification message when a site has entered fullscreen and the directions of how to exit.">
         This site has gone fullscreen.
-Drag from top to exit.
+Hit the back button to exit.
       </message>
 
       <!-- Download UI -->
       <message name="IDS_DOWNLOAD_NO_SDCARD_DLG_TITLE_product_nosdcard" desc="Dialog title [CHAR LIMIT=25]">
         USB storage unavailable
       </message>
       <message name="IDS_DOWNLOAD_NO_SDCARD_DLG_TITLE_product_default" desc="Dialog title [CHAR LIMIT=25]">
         No SD card
       </message>
       <message name="IDS_DOWNLOAD_SDCARD_BUSY_DLG_TITLE_product_nosdcard" desc="Title for a dialog informing the user that the SD card used for external storage is busy so they cannot download anything [CHAR LIMIT=30]">
@@ skipping 155 matching lines @@
       <message name="IDS_FRE_NEW_RECENTS_MENU_TITLE" desc="Title for the Recents Menu what's-new-screen">
         Find your tabs here
       </message>
       <message name="IDS_FRE_NEW_RECENTS_MENU_TEXT" desc="Text for the Recents Menu what's-new-screen">
         Your tabs and apps are now in the same place for easier access.  You can turn this feature off in <ph name="BEGIN_LINK">&lt;link&gt;</ph>Settings<ph name="END_LINK">&lt;/link&gt;</ph>.
       </message>
 
     </messages>
   </release>
 </grit>