Add <link rel=preload> onload support for scripts and styles

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

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef LinkPreloadResourceClients_h
+#define LinkPreloadResourceClients_h
+
+#include "core/fetch/CSSStyleSheetResource.h"
+#include "core/fetch/FontResource.h"
+#include "core/fetch/ImageResourceClient.h"
+#include "core/fetch/ResourceOwner.h"
+#include "core/fetch/ScriptResource.h"
+#include "core/fetch/StyleSheetResourceClient.h"
+
+namespace blink {
+
+class LinkLoader;
+
+class LinkPreloadResourceClient {

[sof, 2016/01/20 12:22:53]

Since this contains a heap reference, you need to trace it. The way we normally
do that for these client base classes is to turn them into GC mixins --


  class LinkPreloadResourceClient : public WillBeGarbageCollectedMixin {
  public:
    ...
      DEFINE_INLINE_VIRTUAL_TRACE()
      {
          visitor->trace(m_loader);
      }
  }

(I think you may have to define that trace in the .cpp file though, as
LinkLoader's definition is not in scope...)

+ have each class that derive from LinkPreloadResourceClient delegate to
LinkPreloadResourceClient::trace(visitor) also.

[Yoav Weiss, 2016/01/20 13:14:01]

Had to define it as NoBaseWillBeGarbageCollectedFinalized, as otherwise, I got
'static_assert failed "only garbage collected objects can have garbage collected
mixins"'

+public:
+    virtual ~LinkPreloadResourceClient() { }
+
+    void triggerEvents(const Resource*) const;
+
+protected:
+    LinkPreloadResourceClient(LinkLoader* loader)
+        : m_loader(loader)
+    {
+        ASSERT(loader);
+    }
+
+private:
+    LinkLoader* m_loader;

[sof, 2016/01/20 12:22:53]

RawPtrWillBeMember<LinkLoader>

[Yoav Weiss, 2016/01/20 13:14:01]

done

+};
+
+class LinkPreloadScriptResourceClient: public ResourceOwner<ScriptResource, ScriptResourceClient>, public LinkPreloadResourceClient {
+public:
+    static PassOwnPtrWillBeRawPtr<LinkPreloadScriptResourceClient> create(LinkLoader* loader, ScriptResource* resource)
+    {
+        return adoptPtrWillBeNoop(new LinkPreloadScriptResourceClient(loader, resource));
+    }
+
+    virtual String debugName() const { return "LinkPreloadScript"; }
+
+    void notifyFinished(Resource* resource) override
+    {
+        ASSERT(this->resource() == resource);
+        triggerEvents(resource);
+    }
+
+    DEFINE_INLINE_VIRTUAL_TRACE()
+    {
+        ResourceOwner<ScriptResource, ScriptResourceClient>::trace(visitor);
+    }
+
+private:
+    LinkPreloadScriptResourceClient(LinkLoader* loader, ScriptResource* resource)
+        : LinkPreloadResourceClient(loader)
+    {
+        setResource(resource);
+    }
+};
+
+class LinkPreloadStyleResourceClient: public ResourceOwner<CSSStyleSheetResource, StyleSheetResourceClient>, public LinkPreloadResourceClient {
+public:
+    static PassOwnPtrWillBeRawPtr<LinkPreloadStyleResourceClient> create(LinkLoader* loader, CSSStyleSheetResource* resource)
+    {
+        return adoptPtrWillBeNoop(new LinkPreloadStyleResourceClient(loader, resource));
+    }
+
+    virtual String debugName() const { return "LinkPreloadStyle"; }
+
+    void setCSSStyleSheet(const String&, const KURL&, const String&, const CSSStyleSheetResource* resource) override
+    {
+        ASSERT(this->resource() == resource);
+        triggerEvents(static_cast<const Resource*>(resource));
+    }
+
+    DEFINE_INLINE_VIRTUAL_TRACE()
+    {
+        ResourceOwner<CSSStyleSheetResource, StyleSheetResourceClient>::trace(visitor);
+    }
+
+private:
+    LinkPreloadStyleResourceClient(LinkLoader* loader, CSSStyleSheetResource* resource)
+        : LinkPreloadResourceClient(loader)
+    {
+        setResource(resource);
+    }
+};
+
+}
+
+#endif // LinkPreloadResourceClients_h