mac: use png otr icon asset instead of pdf

chrome/app/theme/theme_resources.grd

 <?xml version="1.0" encoding="utf-8"?>
 <grit latest_public_release="0" current_release="1">
   <outputs>
     <output filename="grit/theme_resources.h" type="rc_header" context="default_100_percent">
       <emit emit_type='prepend'></emit>
     </output>
     <output filename="grit/theme_resources_map.cc" type="resource_map_source" context="default_100_percent" />
     <output filename="grit/theme_resources_map.h" type="resource_map_header" context="default_100_percent" />
     <output filename="theme_resources_100_percent.pak" type="data_package" context="default_100_percent" />
     <output filename="theme_resources_200_percent.pak" type="data_package" context="default_200_percent" />
@@ skipping 502 matching lines @@
       <structure type="chrome_scaled_image" name="IDR_OMNIBOX_TTS_DARK" file="omnibox_tts_dark.png" />
       <structure type="chrome_scaled_image" name="IDR_OMNIBOX_TTS_SELECTED" file="omnibox_tts_selected.png" />
       <if expr="pp_ifdef('chromeos')">
         <structure type="chrome_scaled_image" name="IDR_OOBE_PROGRESS_DOT_CURRENT" file="oobe_progress_dot_current.png" />
         <structure type="chrome_scaled_image" name="IDR_OOBE_PROGRESS_DOT_EMPTY" file="oobe_progress_dot_empty.png" />
         <structure type="chrome_scaled_image" name="IDR_OOBE_PROGRESS_DOT_FILLED" file="oobe_progress_dot_filled.png" />
         <structure type="chrome_scaled_image" name="IDR_OOBE_PROGRESS_LINE" file="oobe_progress_line.png" />
         <structure type="chrome_scaled_image" name="IDR_OOBE_PROGRESS_LINE_LEFT" file="oobe_progress_line_left.png" />
         <structure type="chrome_scaled_image" name="IDR_OOBE_PROGRESS_LINE_RIGHT" file="oobe_progress_line_right.png" />
       </if>
-      <if expr="not pp_ifdef('toolkit_views')">
+      <if expr="not pp_ifdef('toolkit_views') and not is_macosx">
         <structure type="chrome_scaled_image" name="IDR_OTR_ICON" file="otr_icon.png" />
       </if>
       <if expr="pp_ifdef('toolkit_views')">
         <if expr="not pp_ifdef('use_ash')">
           <structure type="chrome_scaled_image" name="IDR_OTR_ICON" file="common/otr_icon.png" />
         </if>
         <if expr="pp_ifdef('use_ash')">
           <structure type="chrome_scaled_image" name="IDR_OTR_ICON" file="cros/otr_icon.png" />
         </if>
       </if>
+      <if expr="is_macosx">
+        <structure type="chrome_scaled_image" name="IDR_OTR_ICON" file="mac/otr_icon.png" />
+      </if>
       <if expr="context.startswith('default_')">
         <structure type="chrome_scaled_image" name="IDR_OTR_ICON_FULLSCREEN" file="otr_icon.png" />
       </if>
       <if expr="not context.startswith('default_')">
         <structure type="chrome_scaled_image" name="IDR_OTR_ICON_FULLSCREEN" file="otr_icon_fullscreen.png" />
       </if>
       <structure type="chrome_scaled_image" name="IDR_PAGEINFO_BAD" file="pageinfo_bad.png" />
       <structure type="chrome_scaled_image" name="IDR_PAGEINFO_GOOD" file="pageinfo_good.png" />
       <structure type="chrome_scaled_image" name="IDR_PAGEINFO_INFO" file="pageinfo_info.png" />
       <structure type="chrome_scaled_image" name="IDR_PAGEINFO_WARNING_MAJOR" file="pageinfo_warning_major.png" />
@@ skipping 368 matching lines @@
         <if expr="not is_macosx">
           <include name="IDR_STATUS_TRAY_ICON" file="chromium/product_logo_22.png" type="BINDATA" />
           <include name="IDR_STATUS_TRAY_ICON_PRESSED" file="chromium/product_logo_22.png" type="BINDATA" />
         </if>
         <include name="IDR_WIZARD_ICON" file="chromium/wizard_icon.png" type="BINDATA" />
         <include name="IDR_WIZARD_ICON_RTL" file="chromium/wizard_icon_rtl.png" type="BINDATA" />
       </if>
     </includes>
   </release>
 </grit>