Add a runtime flag in WebRuntimeFeatures to enable 'image/webp' accept header

Source/WebCore/loader/cache/CachedImage.cpp

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
     Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
     Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
@@ skipping 29 matching lines @@
 #include <wtf/CurrentTime.h>
 #include <wtf/MemoryInstrumentationHashMap.h>
 #include <wtf/MemoryObjectInfo.h>
 #include <wtf/StdLibExtras.h>
 #include <wtf/Vector.h>
 
 #if ENABLE(SVG)
 #include "SVGImage.h"
 #endif
 
+#if USE(WEBP)
+#include "RuntimeEnabledFeatures.h"
+#endif
+
 using std::max;
 
 namespace WebCore {
 
 CachedImage::CachedImage(const ResourceRequest& resourceRequest)
     : CachedResource(resourceRequest, ImageResource)
     , m_image(0)
 {
     setStatus(Unknown);
+    setCustomAcceptHeader();
 }
 
 CachedImage::CachedImage(Image* image)
     : CachedResource(ResourceRequest(), ImageResource)
     , m_image(image)
 {
     setStatus(Cached);
     setLoading(false);
+    setCustomAcceptHeader();
 }
 
 CachedImage::~CachedImage()
 {
     clearImage();
 }
 
 void CachedImage::load(CachedResourceLoader* cachedResourceLoader, const ResourceLoaderOptions& options)
 {
     if (!cachedResourceLoader || cachedResourceLoader->autoLoadImages())
@@ skipping 209 matching lines @@
 }
 
 void CachedImage::clear()
 {
     destroyDecodedData();
     clearImage();
     m_pendingContainerSizeRequests.clear();
     setEncodedSize(0);
 }
 
+void CachedImage::setCustomAcceptHeader()
+{
+#if USE(WEBP)
+    if (RuntimeEnabledFeatures::webPInAcceptHeaderEnabled())
+        setAccept("image/webp,*/*;q=0.8");
+#endif
+}
+
 inline void CachedImage::createImage()
 {
     // Create the image if it doesn't yet exist.
     if (m_image)
         return;
 #if ENABLE(SVG)
     else if (m_response.mimeType() == "image/svg+xml") {
         RefPtr<SVGImage> svgImage = SVGImage::create(this);
         m_svgImageCache = SVGImageCache::create(svgImage.get());
         m_image = svgImage.release();
@@ skipping 152 matching lines @@
 
 bool CachedImage::currentFrameKnownToBeOpaque(const RenderObject* renderer)
 {
     Image* image = imageForRenderer(renderer);
     if (image->isBitmapImage())
         image->nativeImageForCurrentFrame(); // force decode
     return image->currentFrameKnownToBeOpaque();
 }
 
 } // namespace WebCore