Add Blink support for showing image placeholders using range requests.

third_party/WebKit/Source/core/fetch/Resource.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, 2008, 2009, 2010, 2011 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
@@ skipping 918 matching lines @@
 }
 
 void Resource::setCachePolicyBypassingCache() {
   m_resourceRequest.setCachePolicy(WebCachePolicy::BypassingCache);
 }
 
 void Resource::setLoFiStateOff() {
   m_resourceRequest.setLoFiState(WebURLRequest::LoFiOff);
 }
 
+void Resource::clearRangeRequestHeader() {
+  m_resourceRequest.clearHTTPHeaderField("range");
+}
+
 void Resource::revalidationSucceeded(
     const ResourceResponse& validatingResponse) {
   SECURITY_CHECK(m_redirectChain.isEmpty());
   SECURITY_CHECK(equalIgnoringFragmentIdentifier(validatingResponse.url(),
                                                  m_response.url()));
   m_response.setResourceLoadTiming(validatingResponse.resourceLoadTiming());
 
   // RFC2616 10.3.5
   // Update cached headers from the 304 response
   const HTTPHeaderMap& newHeaders = validatingResponse.httpHeaderFields();
@@ skipping 153 matching lines @@
     case Resource::TextTrack:
     case Resource::Media:
     case Resource::Manifest:
       return false;
   }
   NOTREACHED();
   return false;
 }
 
 }  // namespace blink