libyuv r1629 roll for AVX2 optimized HalfFloatPlane and ExtractAlpha.

cc/resources/video_resource_updater_unittest.cc

 // Copyright 2013 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 "cc/resources/video_resource_updater.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/bind.h"
@@ skipping 530 matching lines @@
   for (int bits = 9; bits <= 12; bits++) {
     int num_values = 1 << bits;
     for (int i = 0; i < num_values; i++)
       integers[i] = i;
 
     VideoResourceUpdater::MakeHalfFloats(integers, bits, num_values,
                                          half_floats);
 
     // Multiplier to converting integers to 0.0..1.0 range.
     double multiplier = 1.0 / (num_values - 1);
+    float expected_precision = 0.f;
 
     for (int i = 0; i < num_values; i++) {
       // We expect the result to be within +/- one least-significant bit.
       // Within the range we care about, half-floats values and
       // their representation both sort in the same order, so we
       // can just add one to get the next bigger half-float.
-      float expected_precision =
+      if (i < num_values - 1) {

[hubbe, 2016/10/20 18:55:11]

Why is this change needed?
It seems it will just use the previous expected precision for the last number.
That doesn't seem bad, but why do we need it?

[fbarchard1, 2016/10/20 22:57:34]

Done.  unittest does not need a change.

+        expected_precision =
           FromHalfFloat(half_floats[i] + 1) - FromHalfFloat(half_floats[i]);
+      }
       EXPECT_NEAR(FromHalfFloat(half_floats[i]), integers[i] * multiplier,
                   expected_precision)
           << "i = " << i << " bits = " << bits;
     }
   }
 }
 
 }  // namespace
 }  // namespace cc