Show the image header for the Context Menu

chrome/android/java/strings/android_chrome_strings.grd

Index: chrome/android/java/strings/android_chrome_strings.grd
diff --git a/chrome/android/java/strings/android_chrome_strings.grd b/chrome/android/java/strings/android_chrome_strings.grd
index d35715a295918a2f946e4fe2ff738561af77f976..46714569a924d8e5bc3f68086357a08c5481937b 100644
--- a/chrome/android/java/strings/android_chrome_strings.grd
+++ b/chrome/android/java/strings/android_chrome_strings.grd
@@ -2791,6 +2791,9 @@ You must have Bluetooth and Location turned on in order to use the Physical Web.
       <message name="IDS_CONTEXTMENU_VIDEO_TITLE" desc="The title of a context menu tab when the item pressed contains more than one type. This indicates that all the actions are related to a video.">
         VIDEO
       </message>
+      <message name="IDS_CONTEXT_MENU_HEADER_IMAGE_DEFAULT_DESC_TEXT" desc="The image shown before a thumbnail loads within the context menu.">
+        A thumbnail of the image that was long pressed when accessing the context menu.
+      </message>
     </messages>
   </release>
 </grit>