Revert "Make DocumentThreadableLoader a ResourceOwner"

This reverts commit ae15c135.

Reason for revert:
https://bugs.chromium.org/p/chromium/issues/detail?id=791291
https://bugs.chromium.org/p/chromium/issues/detail?id=791316
https://bugs.chromium.org/p/chromium/issues/detail?id=791288
https://bugs.chromium.org/p/chromium/issues/detail?id=791348
https://bugs.chromium.org/p/chromium/issues/detail?id=791347
https://bugs.chromium.org/p/chromium/issues/detail?id=791450
https://bugs.chromium.org/p/chromium/issues/detail?id=791300
https://bugs.chromium.org/p/chromium/issues/detail?id=791522

Original change's description:
> Make DocumentThreadableLoader a ResourceOwner
> 
> It had a custom implementation to support use of RawResourceClientStateChecker.
> Separate these.
> 
> Bug: 790778, 640291
> Change-Id: Id8a29a5ad916429969b47a0258675437de284b55
> Reviewed-on: https://chromium-review.googlesource.com/802094
> Commit-Queue: Nate Chapin <japhet@chromium.org>
> Reviewed-by: Hiroshige Hayashizaki <hiroshige@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#521177}

TBR=hiroshige@chromium.org,japhet@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 790778, 640291
Change-Id: I15938754b57b8142f8d7e9c94f8aff9bdd8329ed
Reviewed-on: https://chromium-review.googlesource.com/806794Reviewed-by: Nate Chapin <japhet@chromium.org>
Reviewed-by: Hiroshige Hayashizaki <hiroshige@chromium.org>
Commit-Queue: Nate Chapin <japhet@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521448}

third_party/WebKit/Source/core/loader/DocumentThreadableLoader.cpp

@@ -53,7 +53,6 @@
 #include "platform/loader/fetch/FetchUtils.h"
 #include "platform/loader/fetch/Resource.h"
 #include "platform/loader/fetch/ResourceFetcher.h"
-#include "platform/loader/fetch/ResourceLoader.h"
 #include "platform/loader/fetch/ResourceLoaderOptions.h"
 #include "platform/loader/fetch/ResourceRequest.h"
 #include "platform/weborigin/SchemeRegistry.h"
@@ -537,7 +536,7 @@ void DocumentThreadableLoader::MakeCrossOriginAccessRequestBlinkCORS(
 
 DocumentThreadableLoader::~DocumentThreadableLoader() {
   CHECK(!client_);
-  DCHECK(!GetResource());
+  DCHECK(!resource_);
 }
 
 void DocumentThreadableLoader::OverrideTimeout(
@@ -586,16 +585,14 @@ void DocumentThreadableLoader::Detach() {
 }
 
 void DocumentThreadableLoader::SetDefersLoading(bool value) {
-  if (GetResource() && GetResource()->Loader())
-    GetResource()->Loader()->SetDefersLoading(value);
+  if (GetResource())
+    GetResource()->SetDefersLoading(value);
 }
 
 void DocumentThreadableLoader::Clear() {
   client_ = nullptr;
   timeout_timer_.Stop();
   request_started_seconds_ = 0.0;
-  if (GetResource())
-    checker_.WillRemoveClient();
   ClearResource();
 }
 
@@ -737,8 +734,6 @@ bool DocumentThreadableLoader::RedirectReceivedBlinkCORS(
 
   // FIXME: consider combining this with CORS redirect handling performed by
   // CrossOriginAccessControl::handleRedirect().
-  if (GetResource())
-    checker_.WillRemoveClient();
   ClearResource();
 
   // If
@@ -1106,8 +1101,6 @@ void DocumentThreadableLoader::DidTimeout(TimerBase* timer) {
 }
 
 void DocumentThreadableLoader::LoadFallbackRequestForServiceWorker() {
-  if (GetResource())
-    checker_.WillRemoveClient();
   ClearResource();
   ResourceRequest fallback_request(fallback_request_for_service_worker_);
   fallback_request_for_service_worker_ = ResourceRequest();
@@ -1123,8 +1116,6 @@ void DocumentThreadableLoader::LoadActualRequest() {
   actual_request_ = ResourceRequest();
   actual_options_ = ResourceLoaderOptions();
 
-  if (GetResource())
-    checker_.WillRemoveClient();
   ClearResource();
 
   PrepareCrossOriginRequest(actual_request);
@@ -1209,8 +1200,6 @@ void DocumentThreadableLoader::LoadRequestAsync(
   } else {
     SetResource(RawResource::Fetch(new_params, fetcher));
   }
-  if (GetResource())
-    checker_.WillAddClient();
 
   if (!GetResource()) {
     probe::documentThreadableLoaderFailedToStartLoadingForClient(
@@ -1376,6 +1365,7 @@ ExecutionContext* DocumentThreadableLoader::GetExecutionContext() const {
 }
 
 void DocumentThreadableLoader::Trace(blink::Visitor* visitor) {
+  visitor->Trace(resource_);
   visitor->Trace(loading_context_);
   ThreadableLoader::Trace(visitor);
   RawResourceClient::Trace(visitor);

third_party/WebKit/Source/core/loader/DocumentThreadableLoader.h

@@ -57,9 +57,8 @@ class ThreadableLoadingContext;
 
 // TODO(horo): We are using this class not only in documents, but also in
 // workers. We should change the name to ThreadableLoaderImpl.
-class CORE_EXPORT DocumentThreadableLoader final
-    : public ThreadableLoader,
-      private ResourceOwner<RawResource> {
+class CORE_EXPORT DocumentThreadableLoader final : public ThreadableLoader,
+                                                   private RawResourceClient {
   USING_GARBAGE_COLLECTED_MIXIN(DocumentThreadableLoader);
 
  public:
@@ -204,6 +203,32 @@ class CORE_EXPORT DocumentThreadableLoader final
   void LoadRequest(ResourceRequest&, ResourceLoaderOptions);
   bool IsAllowedRedirect(network::mojom::FetchRequestMode, const KURL&) const;
 
+  // TODO(hiroshige): After crbug.com/633696 is fixed,
+  // - Remove RawResourceClientStateChecker logic,
+  // - Make DocumentThreadableLoader to be a ResourceOwner and remove this
+  //   re-implementation of ResourceOwner, and
+  // - Consider re-applying RawResourceClientStateChecker in a more
+  //   general fashion (crbug.com/640291).
+  RawResource* GetResource() const { return resource_.Get(); }
+  void ClearResource() { SetResource(nullptr); }
+  void SetResource(RawResource* new_resource) {
+    if (new_resource == resource_)
+      return;
+
+    if (RawResource* old_resource = resource_.Release()) {
+      checker_.WillRemoveClient();
+      old_resource->RemoveClient(this);
+    }
+
+    if (new_resource) {
+      resource_ = new_resource;
+      checker_.WillAddClient();
+      resource_->AddClient(this);
+    }
+  }
+  Member<RawResource> resource_;
+  // End of ResourceOwner re-implementation, see above.
+
   SecurityOrigin* GetSecurityOrigin() const;
 
   // Returns null if the loader is not associated with Document.

third_party/WebKit/Source/platform/loader/fetch/RawResource.cpp

@@ -31,6 +31,7 @@
 #include "platform/loader/fetch/MemoryCache.h"
 #include "platform/loader/fetch/ResourceClientWalker.h"
 #include "platform/loader/fetch/ResourceFetcher.h"
+#include "platform/loader/fetch/ResourceLoader.h"
 #include "platform/network/http_names.h"
 #include "platform/scheduler/child/web_scheduler.h"
 #include "public/platform/Platform.h"
@@ -295,6 +296,11 @@ void RawResource::NotifyFinished() {
   Resource::NotifyFinished();
 }
 
+void RawResource::SetDefersLoading(bool defers) {
+  if (Loader())
+    Loader()->SetDefersLoading(defers);
+}
+
 static bool ShouldIgnoreHeaderForCacheReuse(AtomicString header_name) {
   // FIXME: This list of headers that don't affect cache policy almost certainly
   // isn't complete.

third_party/WebKit/Source/platform/loader/fetch/RawResource.h

@@ -66,6 +66,12 @@ class PLATFORM_EXPORT RawResource final : public Resource {
     return CreateForTest(KURL(url), type);
   }
 
+  // FIXME: AssociatedURLLoader shouldn't be a DocumentThreadableLoader and
+  // therefore shouldn't use RawResource. However, it is, and it needs to be
+  // able to defer loading. This can be fixed by splitting CORS preflighting out
+  // of DocumentThreadableLoader.
+  void SetDefersLoading(bool);
+
   // Resource implementation
   bool CanReuse(const FetchParameters&) const override;
   bool WillFollowRedirect(const ResourceRequest&,