Create the base Custom Context Menu Dialog.

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 c05c3bc194836a07f128539a57d05cf9441bb547..9af6239d9a836651c1882f9265f94044cde3cb1a 100644
--- a/chrome/android/java/strings/android_chrome_strings.grd
+++ b/chrome/android/java/strings/android_chrome_strings.grd
@@ -2773,6 +2773,15 @@ 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_ROW_ICON_DESCRIPTION" desc="The description of the icon next to an item in a context menu.">
+        An icon that represents the item action and title.

[David Trainor- moved to gerrit, 2017/03/21 16:30:03]

Should we be setting these to text based on the actual icon we're setting?  This
doesn't seem very useful for accessibility?

[JJ, 2017/03/22 23:35:33]

It's not :c I tried it out last week and didn't like it. We could do some
templating here? Like maybe
"$1 Icon" or "An icon that represents $1". Which would be equal to "Open in New
Tab Icon" and write in the description some possibilities.
Thoughts?

[David Trainor- moved to gerrit, 2017/03/23 04:58:47]

I'd be fine with "$1 icon"

+      </message>
+      <message name="IDS_CONTEXT_MENU_ROW_SHARE_ICON_DESCRIPTION" desc="The description of the icon next to the share menu item within a context menu.">
+        An icon that represents the most recently used app when sharing in Chrome.
+      </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>