Vectorize MD otr frame icon

chrome/app/theme/theme_resources.grd

 <?xml version="1.0" encoding="utf-8"?>
 <!-- This grd file contains images that are pre-scaled for device scale
      factors. The image returned by |base::ResourceBundle::GetImageNamed|
      will contain multiple |gfx:ImageSkiaReps| for each scale factors. The
      |fallback_to_low_resolution| attribute controls behavior when
      an image file is missing for target scale factor. If true, chrome
      will automatically scale the 1x image to the target scale factor.
      If false, build will fail due to missing resources. This is
      currently set to true for all resources, but the default will
      become false in near future.
@@ skipping 524 matching lines @@
       <structure type="chrome_scaled_image" name="IDR_OMNIBOX_SELECTED_KEYWORD_BUBBLE_LEFT" file="common/omnibox_selected_keyword_bubble_left.png" />
       <structure type="chrome_scaled_image" name="IDR_OMNIBOX_SELECTED_KEYWORD_BUBBLE_RIGHT" file="common/omnibox_selected_keyword_bubble_right.png" />
       <structure type="chrome_scaled_image" name="IDR_OMNIBOX_SELECTED_KEYWORD_BUBBLE_TOP" file="common/omnibox_selected_keyword_bubble_top.png" />
       <structure type="chrome_scaled_image" name="IDR_OMNIBOX_SELECTED_KEYWORD_BUBBLE_TOP_LEFT" file="common/omnibox_selected_keyword_bubble_top_left.png" />
       <structure type="chrome_scaled_image" name="IDR_OMNIBOX_SELECTED_KEYWORD_BUBBLE_TOP_RIGHT" file="common/omnibox_selected_keyword_bubble_top_right.png" />
       <structure type="chrome_scaled_image" name="IDR_OMNIBOX_STAR" file="common/omnibox_star.png" />
       <structure type="chrome_scaled_image" name="IDR_OMNIBOX_STAR_SELECTED" file="common/omnibox_star_selected.png" />
       <structure type="chrome_scaled_image" name="IDR_OMNIBOX_TTS" file="common/omnibox_tts.png" />
       <structure type="chrome_scaled_image" name="IDR_OMNIBOX_TTS_SELECTED" file="common/omnibox_tts_selected.png" />
       <if expr="toolkit_views and not is_macosx">
-        <!-- In Material Design the Ash image is the same as the common one, so
-             once that mode is always on, these should be collapsed and the
-             duplicate image removed from the tree. -->
+        <!-- This image is not used in Material Design and can be removed when that mode is default. -->
         <if expr="not use_ash">
           <structure type="chrome_scaled_image" name="IDR_OTR_ICON" file="common/otr_icon.png" />
         </if>
         <if expr="use_ash">
           <structure type="chrome_scaled_image" name="IDR_OTR_ICON" file="common/ash/otr_icon.png" />
           <if expr="not chromeos">
             <structure type="chrome_scaled_image" name="IDR_OTR_ICON_DESKTOP" file="common/otr_icon.png" />
           </if>
         </if>
       </if>
@@ skipping 453 matching lines @@
       <!-- People search images -->
       <structure type="chrome_scaled_image" name="IDR_PEOPLE_SEARCH_ACTION_EMAIL" file="common/mail.png" />
       <structure type="chrome_scaled_image" name="IDR_PEOPLE_SEARCH_ACTION_EMAIL_HOVER" file="common/mail_hover.png" />
       <structure type="chrome_scaled_image" name="IDR_PEOPLE_SEARCH_ACTION_EMAIL_PRESSED" file="common/mail_pressed.png" />
       <structure type="chrome_scaled_image" name="IDR_PEOPLE_SEARCH_ACTION_CHAT" file="common/chat.png" />
       <structure type="chrome_scaled_image" name="IDR_PEOPLE_SEARCH_ACTION_CHAT_HOVER" file="common/chat_hover.png" />
       <structure type="chrome_scaled_image" name="IDR_PEOPLE_SEARCH_ACTION_CHAT_PRESSED" file="common/chat_pressed.png" />
     </structures>
   </release>
 </grit>