| Index: Source/core/page/UseCounter.h
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| diff --git a/Source/core/page/UseCounter.h b/Source/core/page/UseCounter.h
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| index cfd3b1d7d0db7a91ee950fceca30c7090c95725d..921c53de34218aa84801bb3cd82eded18d0cf29c 100644
 | 
| --- a/Source/core/page/UseCounter.h
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| +++ b/Source/core/page/UseCounter.h
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| @@ -131,6 +131,7 @@ public:
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|          PrefixedMediaGenerateKeyRequest,
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|          WebAudioLooping,
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|          DocumentClear,
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| +        PrefixedTransitionMediaFeature,
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|          // Add new features above this line. Don't change assigned numbers of each items.
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|          NumberOfFeatures, // This enum value must be last.
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|      };
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| 
 |