Remove blink::Resource::Type::LinkPrefetch and replace it by a flag

third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp

Index: third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
diff --git a/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp b/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
index c4ab711b0903d38ea0d8121df4aa7cffac881516..c517ce509347d4cb9900c1ff0ff98c063d30efab 100644
--- a/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
+++ b/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
@@ -81,7 +81,6 @@ enum SriResourceIntegrityMismatchEvent {
         DEFINE_SINGLE_RESOURCE_HISTOGRAM(prefix, Font)           \
         DEFINE_SINGLE_RESOURCE_HISTOGRAM(prefix, Image)          \
         DEFINE_SINGLE_RESOURCE_HISTOGRAM(prefix, ImportResource) \
-        DEFINE_SINGLE_RESOURCE_HISTOGRAM(prefix, LinkPrefetch)   \
         DEFINE_SINGLE_RESOURCE_HISTOGRAM(prefix, LinkPreload)    \
         DEFINE_SINGLE_RESOURCE_HISTOGRAM(prefix, MainResource)   \
         DEFINE_SINGLE_RESOURCE_HISTOGRAM(prefix, Manifest)       \
@@ -126,8 +125,6 @@ static ResourceLoadPriority typeToPriority(Resource::Type type)
     case Resource::SVGDocument:
         // Also async scripts (set explicitly in loadPriority)
         return ResourceLoadPriorityLow;
-    case Resource::LinkPrefetch:
-        return ResourceLoadPriorityVeryLow;
     }
 
     ASSERT_NOT_REACHED();
@@ -137,6 +134,8 @@ static ResourceLoadPriority typeToPriority(Resource::Type type)
 ResourceLoadPriority ResourceFetcher::computeLoadPriority(Resource::Type type, const FetchRequest& request, ResourcePriority::VisibilityStatus visibility)
 {
     ResourceLoadPriority priority = typeToPriority(type);
+    if (request.isPrefetch())
+        priority = ResourceLoadPriorityVeryLow;
 
     // Visible resources (images in practice) get a boost to High priority.
     if (visibility == ResourcePriority::Visible)
@@ -198,8 +197,6 @@ static WebURLRequest::RequestContext requestContextFromType(bool isMainFrame, Re
         return WebURLRequest::RequestContextSubresource;
     case Resource::ImportResource:
         return WebURLRequest::RequestContextImport;
-    case Resource::LinkPrefetch:
-        return WebURLRequest::RequestContextPrefetch;
     case Resource::LinkPreload:
         return WebURLRequest::RequestContextSubresource;
     case Resource::TextTrack:
@@ -428,6 +425,10 @@ Resource* ResourceFetcher::requestResource(FetchRequest& request, const Resource
 
     unsigned long identifier = createUniqueIdentifier();
     request.mutableResourceRequest().setPriority(computeLoadPriority(factory.type(), request, ResourcePriority::NotVisible));
+    if (request.isPrefetch()) {
+        request.mutableResourceRequest().setHTTPHeaderField(HTTPNames::Purpose, "prefetch");
+        request.mutableResourceRequest().setRequestContext(WebURLRequest::RequestContextPrefetch);
+    }
     initializeResourceRequest(request.mutableResourceRequest(), factory.type(), request.defer());
     context().willStartLoadingResource(identifier, request.mutableResourceRequest(), factory.type());
     if (!request.url().isValid())
@@ -551,8 +552,6 @@ void ResourceFetcher::initializeResourceRequest(ResourceRequest& request, Resour
         request.setCachePolicy(context().resourceRequestCachePolicy(request, type, defer));
     if (request.requestContext() == WebURLRequest::RequestContextUnspecified)
         determineRequestContext(request, type);
-    if (type == Resource::LinkPrefetch)
-        request.setHTTPHeaderField(HTTPNames::Purpose, "prefetch");
 
     context().addAdditionalRequestHeaders(request, (type == Resource::MainResource) ? FetchMainResource : FetchSubresource);
 }