[Android] Support ALPHA_8 UI resources

ui/android/java/src/org/chromium/ui/resources/system/SystemResourceLoader.java

Index: ui/android/java/src/org/chromium/ui/resources/system/SystemResourceLoader.java
diff --git a/ui/android/java/src/org/chromium/ui/resources/system/SystemResourceLoader.java b/ui/android/java/src/org/chromium/ui/resources/system/SystemResourceLoader.java
index c2990f03b077a3b041ccabba09d8ae52dd4132e9..2f74ce9f4116375ad85f58bfc173c3cb2dacb935 100644
--- a/ui/android/java/src/org/chromium/ui/resources/system/SystemResourceLoader.java
+++ b/ui/android/java/src/org/chromium/ui/resources/system/SystemResourceLoader.java
@@ -89,7 +89,7 @@ public class SystemResourceLoader extends AsyncPreloadResourceLoader {
         arcPaint.setAlpha(0xBB);
         arcPaint.setStyle(Style.FILL);
 
-        Bitmap bitmap = Bitmap.createBitmap((int) arcWidth, (int) height, Bitmap.Config.ARGB_8888);
+        Bitmap bitmap = Bitmap.createBitmap((int) arcWidth, (int) height, Bitmap.Config.ALPHA_8);
         Canvas canvas = new Canvas(bitmap);
         canvas.drawArc(arcRect, 45, 90, true, arcPaint);