core/loader: create private directory to store private classes

third_party/WebKit/Source/core/loader/BUILD.gn

Index: third_party/WebKit/Source/core/loader/BUILD.gn
diff --git a/third_party/WebKit/Source/core/loader/BUILD.gn b/third_party/WebKit/Source/core/loader/BUILD.gn
index e0e57be85465879036782dc1e77b671e9cfa51fb..be6e6a636cd4852d6e78eef932eae3e230362248 100644
--- a/third_party/WebKit/Source/core/loader/BUILD.gn
+++ b/third_party/WebKit/Source/core/loader/BUILD.gn
@@ -7,7 +7,6 @@ import("//third_party/WebKit/Source/core/core.gni")
 blink_core_sources("loader") {
   sources = [
     "CookieJar.cpp",
-    "CrossOriginPreflightResultCache.cpp",
     "DocumentLoadTiming.cpp",
     "DocumentLoader.cpp",
     "DocumentThreadableLoader.cpp",
@@ -17,8 +16,6 @@ blink_core_sources("loader") {
     "EmptyClients.cpp",
     "EmptyClients.h",
     "FormSubmission.cpp",
-    "FrameClientHintsPreferencesContext.cpp",
-    "FrameClientHintsPreferencesContext.h",
     "FrameFetchContext.cpp",
     "FrameFetchContext.h",
     "FrameLoadRequest.cpp",
@@ -41,8 +38,6 @@ blink_core_sources("loader") {
     "NavigationScheduler.cpp",
     "PingLoader.cpp",
     "PingLoader.h",
-    "PrerenderHandle.cpp",
-    "PrerenderHandle.h",
     "PrerendererClient.cpp",
     "PrerendererClient.h",
     "ProgressTracker.cpp",
@@ -63,6 +58,12 @@ blink_core_sources("loader") {
     "appcache/ApplicationCacheHost.cpp",
     "appcache/ApplicationCacheHost.h",
     "modulescript/ModuleScriptFetchRequest.h",
+    "private/CrossOriginPreflightResultCache.cpp",
+    "private/CrossOriginPreflightResultCache.h",
+    "private/FrameClientHintsPreferencesContext.cpp",
+    "private/FrameClientHintsPreferencesContext.h",
+    "private/PrerenderHandle.cpp",
+    "private/PrerenderHandle.h",
     "resource/CSSStyleSheetResource.cpp",
     "resource/CSSStyleSheetResource.h",
     "resource/DocumentResource.cpp",