Fix constants in constraints util tests.

content/renderer/media/media_stream_constraints_util_video_device_unittest.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/media/media_stream_constraints_util_video_device.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/optional.h"
@@ skipping 229 matching lines @@
 
   constraint_factory_.Reset();
   constraint_factory_.basic().aspectRatio.setMin(123467890.0);
   result = SelectSettings();
   EXPECT_FALSE(result.HasValue());
   EXPECT_EQ(constraint_factory_.basic().aspectRatio.name(),
             result.failed_constraint_name());
 
   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());
   EXPECT_EQ(constraint_factory_.basic().aspectRatio.name(),
             result.failed_constraint_name());
 }
 
 TEST_F(MediaStreamConstraintsUtilVideoDeviceTest, OverconstrainedOnFrameRate) {
   constraint_factory_.Reset();
   constraint_factory_.basic().frameRate.setExact(123467890.0);
@@ skipping 1419 matching lines @@
   constraint_factory_.Reset();
   constraint_factory_.basic().height.setExact(100);
   VideoDeviceCaptureCapabilities capabilities;
   auto result = SelectVideoDeviceCaptureSourceSettings(
       capabilities, constraint_factory_.CreateWebMediaConstraints());
   EXPECT_FALSE(result.HasValue());
   EXPECT_TRUE(std::string(result.failed_constraint_name()).empty());
 }
 
 }  // namespace content