Reduce strictness of length animation DCHECK

third_party/WebKit/Source/core/animation/CSSLengthInterpolationType.cpp

 // Copyright 2015 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 "core/animation/CSSLengthInterpolationType.h"
 
 #include "core/animation/LengthInterpolationFunctions.h"
 #include "core/animation/LengthPropertyFunctions.h"
 #include "core/animation/css/CSSAnimatableValueFactory.h"
 #include "core/css/CSSCalculationValue.h"
@@ skipping 140 matching lines @@
 #if DCHECK_IS_ON()
     // Assert that setting the length on ComputedStyle directly is identical to
     // the StyleBuilder code path. This check is useful for catching differences
     // in clamping behaviour.
     Length before;
     Length after;
     DCHECK(LengthPropertyFunctions::getLength(cssProperty(), style, before));
     StyleBuilder::applyProperty(cssProperty(), state,
                                 *CSSValue::create(length, zoom));
     DCHECK(LengthPropertyFunctions::getLength(cssProperty(), style, after));
-    DCHECK_EQ(before.type(), after.type());
+    DCHECK_EQ(before.isSpecified(), after.isSpecified());

[suzyh_UTC10 (ex-contributor), 2017/02/14 04:38:51]

I'm not very familiar with LengthType. I think this makes sense for the case
where both before and after are specified, but I'm curious whether it also makes
sense if before.isSpecified() and after.isSpecified() are both false. Should the
type equality check still apply in that case?

[alancutter (OOO until 2018), 2017/02/14 04:46:12]

Good point, added type check back for that case.

     if (before.isSpecified()) {
       const float kSlack = 0.1;
       float delta =
           floatValueForLength(after, 100) - floatValueForLength(before, 100);
       DCHECK_LT(std::abs(delta), kSlack);
     }
 #endif
     return;
   }
   StyleBuilder::applyProperty(cssProperty(), state,
                               *CSSValue::create(length, zoom));
 }
 
 }  // namespace blink