Update avatar button to MD

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 23007e72b2ac9137261de1f27c88c379e868b166..2c2c2862bd37ed912303da603de0ec304d0ef0e8 100644
--- a/chrome/app/theme/theme_resources.grd
+++ b/chrome/app/theme/theme_resources.grd
@@ -433,6 +433,9 @@
         <structure type="chrome_scaled_image" name="IDR_AVATAR_NATIVE_BUTTON_PRESSED_TOP" file="win/avatar_button/win8/sign_in_button_pressed_top.png" />
         <structure type="chrome_scaled_image" name="IDR_AVATAR_NATIVE_BUTTON_PRESSED_TOP_LEFT" file="win/avatar_button/win8/sign_in_button_pressed_top_left.png" />
         <structure type="chrome_scaled_image" name="IDR_AVATAR_NATIVE_BUTTON_PRESSED_TOP_RIGHT" file="win/avatar_button/win8/sign_in_button_pressed_top_right.png" />
+
+        <!-- Windows 10 Material Design -->
+        <structure type="chrome_scaled_image" name="IDR_AVATAR_MD_BUTTON_AVATAR" file="win/avatar_button/win10/sign_in_button_avatar.png" />

[Peter Kasting, 2017/04/26 02:09:53]

Please don't introduce new PNG resources; use vector resources (in .icon format)
instead.

You can easily create .icons from .svgs if the designers supply those, or
(ideally) from the original Material Design icons when they match -- looks like
this is https://material.io/icons/#ic_account_circle .

Check to make sure we don't already have this icon in our tree.

[emx, 2017/04/27 16:30:57]

Done.

       </if>  <!-- toolkit_views and not is_macosx -->
       <if expr="enable_app_list">
         <structure type="chrome_scaled_image" name="IDR_PROFILE_PICTURE_LOADING" file="profile_loading.png" />