tools/benchmarks: Fix failures in image decoding measurements.

tools/perf/benchmarks/image_decoding.py

Index: tools/perf/benchmarks/image_decoding.py
diff --git a/tools/perf/benchmarks/image_decoding.py b/tools/perf/benchmarks/image_decoding.py
index 7c897723d5281a0d9cd4429c381c413ad1afb0c2..2389107f568137de6fa8c68462be2680ef816991 100644
--- a/tools/perf/benchmarks/image_decoding.py
+++ b/tools/perf/benchmarks/image_decoding.py
@@ -26,3 +26,11 @@ class ImageDecodingToughImageCases(perf_benchmark.PerfBenchmark):
 
   def GetExpectations(self):
     return page_sets.ImageDecodingMeasurementStoryExpectations()
+
+  def SetExtraBrowserOptions(self, options):
+    options.AppendExtraBrowserArgs([
+        # Disable asynchronous decodes in the renderer since these test
+        # rely on images have been decoded between consecutive
+        # requestAnimationFrames.
+        '--disable-checker-imaging'
+    ])