Add a way for the gpu veto to report back the reason why it said no

tests/PictureTest.cpp

Index: tests/PictureTest.cpp
diff --git a/tests/PictureTest.cpp b/tests/PictureTest.cpp
index 1ef32abb95ee12986a4ddb65c4047d18cc4012b5..d27b4635838d2991886960864c7b921d293f52b5 100644
--- a/tests/PictureTest.cpp
+++ b/tests/PictureTest.cpp
@@ -730,7 +730,10 @@ static void test_gpu_veto(skiatest::Reporter* reporter) {
     }
     SkAutoTUnref<SkPicture> picture(recorder.endRecording());
     // path effects currently render an SkPicture undesireable for GPU rendering
-    REPORTER_ASSERT(reporter, !picture->suitableForGpuRasterization(NULL));
+
+    const char *reason = NULL;
+    REPORTER_ASSERT(reporter, !picture->suitableForGpuRasterization(NULL, &reason));
+    REPORTER_ASSERT(reporter, NULL != reason);
 
     canvas = recorder.beginRecording(100, 100, NULL, 0);
     {