Fix constants in constraints util tests.

content/renderer/media/media_stream_constraints_util_video_device_unittest.cc

Index: content/renderer/media/media_stream_constraints_util_video_device_unittest.cc
diff --git a/content/renderer/media/media_stream_constraints_util_video_device_unittest.cc b/content/renderer/media/media_stream_constraints_util_video_device_unittest.cc
index 4222ea37bfde4d3088dcc3077b5da4f2b1226286..7a35cf85eeb31570c5ba774ae62fc59e5111c8a2 100644
--- a/content/renderer/media/media_stream_constraints_util_video_device_unittest.cc
+++ b/content/renderer/media/media_stream_constraints_util_video_device_unittest.cc
@@ -247,7 +247,7 @@ TEST_F(MediaStreamConstraintsUtilVideoDeviceTest,
 
   constraint_factory_.Reset();
   // This value is lower than the minimum supported by sources.
-  double kLowAspectRatio = 0.01;
+  const double kLowAspectRatio = 0.01;
   constraint_factory_.basic().aspectRatio.setMax(kLowAspectRatio);
   result = SelectSettings();
   EXPECT_FALSE(result.HasValue());