Apply MD style to Linux avatar buttons.

chrome/app/theme/theme_resources.grd

Index: chrome/app/theme/theme_resources.grd
diff --git a/chrome/app/theme/theme_resources.grd b/chrome/app/theme/theme_resources.grd
index 1bc856021f666412fef4f41a32a4357ff8eb15b6..42d28958a48bb61c4cf976967b1de7b4331bd28b 100644
--- a/chrome/app/theme/theme_resources.grd
+++ b/chrome/app/theme/theme_resources.grd
@@ -333,7 +333,7 @@
       <structure type="chrome_scaled_image" name="IDR_PROFILE_AVATAR_PLACEHOLDER_LARGE" file="common/profile_avatar_placeholder_large.png" />
 
       <!-- New style avatar button -->
-      <if expr="toolkit_views and not is_macosx">
+      <if expr="is_win">

[Lei Zhang, 2017/09/13 07:37:34]

This doesn't match the C++ code. The IDR_AVATAR_THEMED usage in avatar_button.cc
is not inside a #if defined(OS_WIN) conditional. This only works because
output_all_resource_defines defaults to true and
output_all_resource_defines="false" isn't set. See bug 627301.

         <!-- Windows, themed -->
         <structure type="chrome_scaled_image" name="IDR_AVATAR_THEMED_BUTTON_AVATAR" file="win/avatar_button/themed/sign_in_button_avatar.png" />
         <structure type="chrome_scaled_image" name="IDR_AVATAR_THEMED_BUTTON_NORMAL_BOTTOM" file="win/avatar_button/themed/sign_in_button_bottom.png" />