Replace expand PNGs with vector drawables.

app/src/main/java/org/fdroid/fdroid/views/AppDetailsRecyclerViewAdapter.java

@@ -842,8 +842,8 @@ public class AppDetailsRecyclerViewAdapter
                 iconDrawable = DrawableCompat.wrap(iconDrawable).mutate();
                 DrawableCompat.setTint(iconDrawable, Color.parseColor("#B4B4B4"));
             }
-            final Drawable expandLess = ContextCompat.getDrawable(headerView.getContext(), R.drawable.ic_expand_less_grey600);
+            final Drawable expandLess = ContextCompat.getDrawable(headerView.getContext(), R.drawable.ic_expand_less);
-            final Drawable expandMore = ContextCompat.getDrawable(headerView.getContext(), R.drawable.ic_expand_more_grey600);
+            final Drawable expandMore = ContextCompat.getDrawable(headerView.getContext(), R.drawable.ic_expand_more);
             TextViewCompat.setCompoundDrawablesRelativeWithIntrinsicBounds(headerView,
                     iconDrawable, null, isExpanded ? expandLess : expandMore, null);
         }
@@ -1300,7 +1300,7 @@ public class AppDetailsRecyclerViewAdapter
             expandedLayout.setVisibility(expand ? View.VISIBLE : View.GONE);
             versionCode.setVisibility(expand ? View.VISIBLE : View.GONE);
             expandArrow.setImageDrawable(ContextCompat.getDrawable(context, expand ?
-                    R.drawable.ic_expand_less_grey600 : R.drawable.ic_expand_more_grey600));
+                    R.drawable.ic_expand_less : R.drawable.ic_expand_more));
 
             // This is required to make these labels
             // auto-scrollable when they are too long

app/src/main/res/drawable/ic_expand_less.xml

@@ -0,0 +1,5 @@
+<vector android:height="24dp" android:tint="#B4B4B4"
+    android:viewportHeight="24" android:viewportWidth="24"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="#FFFFFF" android:pathData="M12,8l-6,6 1.41,1.41L12,10.83l4.59,4.58L18,14z"/>
+</vector>

app/src/main/res/drawable/ic_expand_more.xml

@@ -0,0 +1,5 @@
+<vector android:height="24dp" android:tint="#B4B4B4"
+    android:viewportHeight="24" android:viewportWidth="24"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="#FFFFFF" android:pathData="M16.59,8.59L12,13.17 7.41,8.59 6,10l6,6 6,-6z"/>
+</vector>

app/src/main/res/layout/app_details2_links.xml

@@ -27,8 +27,8 @@
             android:paddingStart="@dimen/details_activity__collapsable_lists__padding__horizontal"
             android:paddingRight="@dimen/details_activity__collapsable_lists__padding__horizontal"
             android:paddingEnd="@dimen/details_activity__collapsable_lists__padding__horizontal"
-            android:drawableRight="@drawable/ic_expand_more_grey600"
+            android:drawableRight="@drawable/ic_expand_more"
-            android:drawableEnd="@drawable/ic_expand_more_grey600"
+            android:drawableEnd="@drawable/ic_expand_more"
             android:drawableLeft="@drawable/ic_website"
             android:drawableStart="@drawable/ic_website"
             android:background="?selectableItemBackground" />

app/src/main/res/layout/app_details2_version_item.xml

@@ -84,7 +84,7 @@
         <ImageView android:id="@+id/expand_arrow"
             android:layout_width="wrap_content"
             android:layout_height="match_parent"
-            android:src="@drawable/ic_expand_more_grey600" />
+            android:src="@drawable/ic_expand_more" />
     </LinearLayout>
 
     <LinearLayout android:id="@+id/expanded_layout"