[NTP::Downloads] Replace 36dp file type resources with vector drawables.

chrome/android/java/res/values/dimens.xml

Index: chrome/android/java/res/values/dimens.xml
diff --git a/chrome/android/java/res/values/dimens.xml b/chrome/android/java/res/values/dimens.xml
index 8eb4862a3577373ed523d4720afcd85b426d1eab..5d2d43571f07350c7fd48d605be7f0b1aebeff6d 100644
--- a/chrome/android/java/res/values/dimens.xml
+++ b/chrome/android/java/res/values/dimens.xml
@@ -294,6 +294,8 @@
     <dimen name="ntp_sign_in_promo_margin_top">20dp</dimen>
     <dimen name="ntp_progress_indicator_diameter">56dp</dimen>
     <dimen name="snippets_thumbnail_size">72dp</dimen>
+    <!-- file type icon size = snippets_thumbnail_size - 2 * padding -->
+    <dimen name="snippets_thumbnail_file_type_icon_padding">20dp</dimen>
     <dimen name="snippets_thumbnail_margin">16dp</dimen>
     <!-- The default padding for the peeking card and the amount the card peeks by in the current
          peeking card animation (the calculations assume this is the same). -->
@@ -400,6 +402,8 @@
 
     <!-- Downloads dimensions. -->
     <dimen name="downloads_item_icon_size">48dp</dimen>
+    <!-- file type icon size = downloads_item_icon_size - 2 * padding -->
+    <dimen name="downloads_item_file_type_icon_padding">12dp</dimen>
     <dimen name="downloads_item_margin">16dp</dimen>
 
     <!-- SelectableListLayout styles -->