Include all resolutions for several image assets.

This also removes incognito_separator.png, which can be replaced with a
solid-color View.

BUG=289843
R=aurimas@chromium.org, tedchoc@chromium.org

Review URL: https://codereview.chromium.org/339293002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@278120 0039d316-1c4b-4281-b951-d872f2087c98

chrome/android/java/res/layout/accessibility_tab_switcher.xml

@@ -40,12 +40,11 @@
             android:contentDescription="@string/accessibility_tab_switcher_standard_stack"
             style="?android:attr/borderlessButtonStyle" />
 
-        <ImageView
-            android:layout_width="wrap_content"
-            android:layout_height="wrap_content"
+        <View
+            android:layout_width="1px"
+            android:layout_height="18dp"
             android:layout_gravity="center_vertical"
-            android:src="@drawable/incognito_separator"
-            android:contentDescription="@null" />
+            android:background="#292929" />
 
         <ImageButton
             android:id="@+id/incognito_tabs_button"