use 565 bitmap instead of 4444 to improve quality

http://b/2577416

Change-Id: I74f00f700bbe7bc1be9b790e075fec111765341c
diff --git a/src/com/android/browser/BrowserActivity.java b/src/com/android/browser/BrowserActivity.java
index 8a70c56..1c136b3 100644
--- a/src/com/android/browser/BrowserActivity.java
+++ b/src/com/android/browser/BrowserActivity.java
@@ -2380,7 +2380,7 @@
             return null;
         }
         Bitmap bm = Bitmap.createBitmap(getDesiredThumbnailWidth(this),
-                getDesiredThumbnailHeight(this), Bitmap.Config.ARGB_4444);
+                getDesiredThumbnailHeight(this), Bitmap.Config.RGB_565);
         Canvas canvas = new Canvas(bm);
         // May need to tweak these values to determine what is the
         // best scale factor