WTF::notFound looks too much like a local variable.

Source/core/platform/image-decoders/ico/ICOImageDecoder.cpp

Index: Source/core/platform/image-decoders/ico/ICOImageDecoder.cpp
diff --git a/Source/core/platform/image-decoders/ico/ICOImageDecoder.cpp b/Source/core/platform/image-decoders/ico/ICOImageDecoder.cpp
index 7e713c365a76f27a17da9b97f304f725208cf307..230f5e23fae23fa3bc955014195815a1dc416bff 100644
--- a/Source/core/platform/image-decoders/ico/ICOImageDecoder.cpp
+++ b/Source/core/platform/image-decoders/ico/ICOImageDecoder.cpp
@@ -105,7 +105,7 @@ size_t ICOImageDecoder::frameCount()
         m_frameBufferCache.resize(m_dirEntries.size());
         for (size_t i = 0; i < m_dirEntries.size(); ++i) {
             m_frameBufferCache[i].setPremultiplyAlpha(m_premultiplyAlpha);
-            m_frameBufferCache[i].setRequiredPreviousFrameIndex(notFound);
+            m_frameBufferCache[i].setRequiredPreviousFrameIndex(kNotFound);
         }
     }
     // CAUTION: We must not resize m_frameBufferCache again after this, as
@@ -239,7 +239,7 @@ bool ICOImageDecoder::decodeAtIndex(size_t index)
         return setFailed();
     m_frameBufferCache[index] = *m_pngDecoders[index]->frameBufferAtIndex(0);
     m_frameBufferCache[index].setPremultiplyAlpha(m_premultiplyAlpha);
-    m_frameBufferCache[index].setRequiredPreviousFrameIndex(notFound);
+    m_frameBufferCache[index].setRequiredPreviousFrameIndex(kNotFound);
     return !m_pngDecoders[index]->failed() || setFailed();
 }