[MemoryCache] Split UMAs for RevalidationPolicy for preloading/regular requests

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 08cf67e855923ddfb055c55a1454794e5e5dfd6f..ec40106cccc7b12a726f87308e05ce5f1794b3dc 100644
--- a/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
+++ b/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
@@ -391,6 +391,8 @@ ResourcePtr<Resource> ResourceFetcher::requestResource(FetchRequest& request, co
     const RevalidationPolicy policy = determineRevalidationPolicy(factory.type(), request, resource.get(), isStaticData);
 
     String histogramName = "Blink.MemoryCache.RevalidationPolicy.";
+    if (request.forPreload())
+        histogramName.append("Preload.");
     histogramName.append(Resource::resourceTypeName(factory.type()));
     Platform::current()->histogramEnumeration(histogramName.utf8().data(), policy, Load + 1);