SkWebpEncoder: use bgra for lossless and yuv for lossy

Previosuly, we would (accidentally) always use just yuv.

Bug: 713862
Change-Id: I00acc6ca2841ba0636494119b7b4f46a9deee401
Reviewed-on: https://skia-review.googlesource.com/17406
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
diff --git a/tests/EncodeTest.cpp b/tests/EncodeTest.cpp
index 102b4cd..4d0ade1 100644
--- a/tests/EncodeTest.cpp
+++ b/tests/EncodeTest.cpp
@@ -255,6 +255,6 @@
     SkImage::MakeFromEncoded(data2)->asLegacyBitmap(&bm2, SkImage::kRO_LegacyBitmapMode);
     SkImage::MakeFromEncoded(data3)->asLegacyBitmap(&bm3, SkImage::kRO_LegacyBitmapMode);
     REPORTER_ASSERT(r, almost_equals(bm0, bm1, 0));
-    REPORTER_ASSERT(r, almost_equals(bm0, bm2, 6));
+    REPORTER_ASSERT(r, almost_equals(bm0, bm2, 90));
     REPORTER_ASSERT(r, almost_equals(bm2, bm3, 45));
 }