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

Source/core/platform/image-decoders/webp/WEBPImageDecoderTest.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 424 matching lines @@
 
     // Give it data that is enough to parse but not decode in order to check the status
     // of requiredPreviousFrameIndex before decoding.
     size_t partialSize = 1;
     do {
         RefPtr<SharedBuffer> data = SharedBuffer::create(fullData->data(), partialSize);
         decoder->setData(data.get(), false);
         ++partialSize;
     } while (!decoder->frameCount() || decoder->frameBufferAtIndex(0)->status() == ImageFrame::FrameEmpty);
 
-    EXPECT_EQ(notFound, decoder->frameBufferAtIndex(0)->requiredPreviousFrameIndex());
+    EXPECT_EQ(kNotFound, decoder->frameBufferAtIndex(0)->requiredPreviousFrameIndex());
     unsigned frameCount = decoder->frameCount();
     for (size_t i = 1; i < frameCount; ++i)
         EXPECT_EQ(i - 1, decoder->frameBufferAtIndex(i)->requiredPreviousFrameIndex());
 
     decoder->setData(fullData.get(), true);
     for (size_t i = 0; i < frameCount; ++i)
-        EXPECT_EQ(notFound, decoder->frameBufferAtIndex(i)->requiredPreviousFrameIndex());
+        EXPECT_EQ(kNotFound, decoder->frameBufferAtIndex(i)->requiredPreviousFrameIndex());
 }
 
 TEST_F(AnimatedWebPTests, randomFrameDecode)
 {
     testRandomFrameDecode("/LayoutTests/fast/images/resources/webp-animated.webp");
     testRandomFrameDecode("/LayoutTests/fast/images/resources/webp-animated-opaque.webp");
     testRandomFrameDecode("/LayoutTests/fast/images/resources/webp-animated-large.webp");
     testRandomFrameDecode("/LayoutTests/fast/images/resources/webp-animated-icc-xmp.webp");
 }
 
@@ skipping 21 matching lines @@
         RefPtr<SharedBuffer> data = SharedBuffer::create(fullData->data(), partialSize);
         decoder->setData(data.get(), false);
         ++partialSize;
     } while (!decoder->frameCount() || decoder->frameBufferAtIndex(0)->status() == ImageFrame::FrameEmpty);
 
     // Skip to the last frame and clear.
     decoder->setData(fullData.get(), true);
     EXPECT_EQ(frameCount, decoder->frameCount());
     ImageFrame* lastFrame = decoder->frameBufferAtIndex(frameCount - 1);
     EXPECT_EQ(baselineHashes[frameCount - 1], hashSkBitmap(lastFrame->getSkBitmap()));
-    decoder->clearCacheExceptFrame(notFound);
+    decoder->clearCacheExceptFrame(kNotFound);
 
     // Resume decoding of the first frame.
     ImageFrame* firstFrame = decoder->frameBufferAtIndex(0);
     EXPECT_EQ(ImageFrame::FrameComplete, firstFrame->status());
     EXPECT_EQ(baselineHashes[0], hashSkBitmap(firstFrame->getSkBitmap()));
 }
 
 TEST_F(AnimatedWebPTests, decodeAfterReallocatingData)
 {
     testDecodeAfterReallocatingData("/LayoutTests/fast/images/resources/webp-animated.webp");
     testDecodeAfterReallocatingData("/LayoutTests/fast/images/resources/webp-animated-icc-xmp.webp");
 }