Move static methods out of CSSLengthInterpolationType to LengthInterpolationFunctions

third_party/WebKit/Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/KeyframeEffect.idl',
             'animation/AnimationEffectReadOnly.idl',
             'animation/AnimationEffectTiming.idl',
@@ skipping 987 matching lines @@
             'animation/InterpolationEffect.h',
             'animation/InterpolationType.h',
             'animation/InterpolationValue.h',
             'animation/InvalidatableInterpolation.cpp',
             'animation/InvalidatableInterpolation.h',
             'animation/Keyframe.cpp',
             'animation/Keyframe.h',
             'animation/KeyframeEffectModel.cpp',
             'animation/KeyframeEffectModel.h',
             'animation/LegacyStyleInterpolation.h',
+            'animation/LengthInterpolationFunctions.cpp',
+            'animation/LengthInterpolationFunctions.h',
             'animation/LengthListPropertyFunctions.cpp',
             'animation/LengthListPropertyFunctions.h',
             'animation/LengthPropertyFunctions.cpp',
             'animation/LengthPropertyFunctions.h',
             'animation/LengthUnitsChecker.h',
             'animation/ListInterpolationFunctions.cpp',
             'animation/ListInterpolationFunctions.h',
             'animation/NonInterpolableValue.h',
             'animation/NumberAttributeFunctions.h',
             'animation/NumberPropertyFunctions.cpp',
@@ skipping 3276 matching lines @@
             'timing/MemoryInfoTest.cpp',
             'timing/PerformanceBaseTest.cpp',
             'timing/PerformanceObserverTest.cpp',
             'workers/DedicatedWorkerTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'workers/WorkerThreadTestHelper.h',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }