Add Blink support for showing image placeholders using range requests.

third_party/WebKit/Source/core/fetch/ResourceFetcher.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) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All
     rights reserved.
     Copyright (C) 2009 Torch Mobile Inc. http://www.torchmobile.com/
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
@@ skipping 1146 matching lines @@
       if (resource->options().requestInitiatorContext == DocumentContext)
         context().addResourceTiming(*info);
       resource->reportResourceTimingToClients(*info);
     }
   }
   context().dispatchDidFinishLoading(resource->identifier(), finishTime,
                                      encodedDataLength);
   if (finishReason == DidFinishLoading)
     resource->finish(finishTime);
   context().didLoadResource(resource);
+
+  if (resource->isImage() &&
+      toImageResource(resource)->shouldReloadBrokenPlaceholder()) {
+    toImageResource(resource)->reloadIfLoFiOrPlaceholder(this);
+  }
 }
 
 void ResourceFetcher::didFailLoading(Resource* resource,
                                      const ResourceError& error) {
   TRACE_EVENT_ASYNC_END0("blink.net", "Resource", resource->identifier());
   removeResourceLoader(resource->loader());
   m_resourceTimingInfoMap.take(const_cast<Resource*>(resource));
   bool isInternalRequest = resource->options().initiatorInfo.name ==
                            FetchInitiatorTypeNames::internal;
   context().dispatchDidFail(resource->identifier(), error, isInternalRequest);
   resource->error(error);
   context().didLoadResource(resource);
+
+  if (resource->isImage() &&
+      toImageResource(resource)->shouldReloadBrokenPlaceholder()) {
+    toImageResource(resource)->reloadIfLoFiOrPlaceholder(this);
+  }
 }
 
 void ResourceFetcher::didReceiveResponse(Resource* resource,
                                          const ResourceResponse& response,
                                          WebDataConsumerHandle* rawHandle) {
   // |rawHandle|'s ownership is transferred to the callee.
   std::unique_ptr<WebDataConsumerHandle> handle = wrapUnique(rawHandle);
 
   if (response.wasFetchedViaServiceWorker()) {
     if (resource->options().corsEnabled == IsCORSEnabled &&
@@ skipping 227 matching lines @@
         resource->identifier(), resourceLoadPriority,
         resourcePriority.intraPriorityValue);
   }
 }
 
 void ResourceFetcher::reloadLoFiImages() {
   for (const auto& documentResource : m_documentResources) {
     Resource* resource = documentResource.value.get();
     if (resource && resource->isImage()) {
       ImageResource* imageResource = toImageResource(resource);
-      imageResource->reloadIfLoFi(this);
+      imageResource->reloadIfLoFiOrPlaceholder(this);
     }
   }
 }
 
 void ResourceFetcher::logPreloadStats() {
   if (!m_preloads)
     return;
   unsigned scripts = 0;
   unsigned scriptMisses = 0;
   unsigned stylesheets = 0;
@@ skipping 175 matching lines @@
   visitor->trace(m_context);
   visitor->trace(m_archive);
   visitor->trace(m_loaders);
   visitor->trace(m_nonBlockingLoaders);
   visitor->trace(m_documentResources);
   visitor->trace(m_preloads);
   visitor->trace(m_resourceTimingInfoMap);
 }
 
 }  // namespace blink