Add a util method of creating Icon with Drawable

- Add a util method to help create Icon with Drawable so that
users don't need to handle bitmaps
- Add support for creating with ColorDrawable

Test: robotest
Fixes: 124407373
Change-Id: I1897256821cc804a5e599d967feb84a3bcd689a9

tests/robotests/src/com/android/settings/wifi/qrcode/QrCameraTest.java

@@ -22,14 +22,11 @@ import static org.mockito.Mockito.mock;
 
 import android.content.Context;
 import android.graphics.Bitmap;
-import android.graphics.Color;
 import android.graphics.Matrix;
 import android.graphics.Rect;
 import android.graphics.SurfaceTexture;
 import android.util.Size;
 
-import com.android.settings.R;
-
 import com.google.zxing.BinaryBitmap;
 import com.google.zxing.LuminanceSource;
 import com.google.zxing.RGBLuminanceSource;