Disable flaky DeferredImageDecoderTest.decodeOnOtherThread on Mac

TBR=khushalsagar@chromium.org,chrishtr@chromium.org

Bug: 792540
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: I0fb45968230846c0ffb8168d8d31a87bad06fcb5
Reviewed-on: https://chromium-review.googlesource.com/811588Reviewed-by: Ganggui Tang <gogerald@chromium.org>
Commit-Queue: Ganggui Tang <gogerald@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522167}

third_party/WebKit/Source/platform/graphics/DeferredImageDecoderTest.cpp

@@ -27,6 +27,7 @@
 
 #include <memory>
 #include "base/memory/scoped_refptr.h"
+#include "build/build_config.h"
 #include "platform/CrossThreadFunctional.h"
 #include "platform/SharedBuffer.h"
 #include "platform/WebTaskRunner.h"
@@ -204,7 +205,13 @@ static void RasterizeMain(PaintCanvas* canvas, sk_sp<PaintRecord> record) {
   canvas->drawPicture(record);
 }
 
-TEST_F(DeferredImageDecoderTest, decodeOnOtherThread) {
+// Flaky on Mac. crbug.com/792540.
+#if defined(OS_MACOSX)
+#define MAYBE_decodeOnOtherThread DISABLED_decodeOnOtherThread
+#else
+#define MAYBE_decodeOnOtherThread decodeOnOtherThread
+#endif
+TEST_F(DeferredImageDecoderTest, MAYBE_decodeOnOtherThread) {
   lazy_decoder_->SetData(data_, true);
   PaintImage image = CreatePaintImageAtIndex(0);
   ASSERT_TRUE(image);