Add missing includes of SkBlendMode.h

It's being removed from SkPaint.h in https://skia-review.googlesource.com/c/skia/+/611077
and this was all the places I could find in frameworks/base.

We might need another CL for a few other Android repos.

Change-Id: I88d31166ed90356c4c52fbcde6bec6c1655b7cf2
diff --git a/libs/hwui/tests/unit/SkiaCanvasTests.cpp b/libs/hwui/tests/unit/SkiaCanvasTests.cpp
index 50d9f56..87c5216 100644
--- a/libs/hwui/tests/unit/SkiaCanvasTests.cpp
+++ b/libs/hwui/tests/unit/SkiaCanvasTests.cpp
@@ -17,10 +17,19 @@
 #include "tests/common/TestUtils.h"
 
 #include <hwui/Paint.h>
+#include <SkAlphaType.h>
+#include <SkBitmap.h>
+#include <SkBlendMode.h>
+#include <SkCanvas.h>
 #include <SkCanvasStateUtils.h>
+#include <SkColor.h>
 #include <SkColorSpace.h>
+#include <SkColorType.h>
+#include <SkImageInfo.h>
 #include <SkPicture.h>
 #include <SkPictureRecorder.h>
+#include <SkRefCnt.h>
+#include <SkSurface.h>
 #include <gtest/gtest.h>
 
 using namespace android;