Add a layer of indirection between Frame and Page

Source/core/frame/FrameHost.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 10 matching lines @@
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef LinkImport_h
-#define LinkImport_h
+#ifndef FrameHost_h
+#define FrameHost_h
 
-#include "core/html/HTMLImportChildClient.h"
-#include "core/html/LinkResource.h"
 #include "wtf/FastAllocBase.h"
+#include "wtf/Noncopyable.h"
 #include "wtf/PassOwnPtr.h"
-#include "wtf/RefPtr.h"
 
 namespace WebCore {
 
-class Document;
-class HTMLImportChild;
+class Page;
+class Chrome;
+class Settings;
 
-//
-// A LinkResource subclasss used for @rel=import.
-//
-class LinkImport : public LinkResource, public HTMLImportChildClient {
-    WTF_MAKE_FAST_ALLOCATED;
+// FrameHost is the set of global data shared between multiple frames
+// and is provided by the embedder to each frame when created.
+// FrameHost currently corresponds to the Page object in core/page
+// however the concept of a Page is moving up out of Blink.
+// In an out-of-process iframe world, a single Page may have
+// multiple frames in different process, thus Page becomes a
+// browser-level concept and Blink core/ only knows about its Frame (and FrameHost).
+// Separating Page from the rest of core/ through this indirection
+// allows us to slowly refactor Page without breaking the rest of core.
+class FrameHost {
+    WTF_MAKE_NONCOPYABLE(FrameHost); WTF_MAKE_FAST_ALLOCATED;
 public:
+    static PassOwnPtr<FrameHost> create(Page&);
 
-    static PassOwnPtr<LinkImport> create(HTMLLinkElement* owner);
+    // Careful: This function will eventually be removed.
+    Page& page() const { return m_page; }
 
-    explicit LinkImport(HTMLLinkElement* owner);
-    virtual ~LinkImport();
+    Settings& settings() const;
+    Chrome& chrome() const;
 
-    // LinkResource
-    virtual void process() OVERRIDE;
-    virtual Type type() const OVERRIDE { return Import; }
-    virtual void ownerRemoved() OVERRIDE;
-    virtual bool hasLoaded() const OVERRIDE;
-
-    // HTMLImportChildClient
-    virtual void didFinish() OVERRIDE;
-    virtual void loaderWillBeDestroyed() OVERRIDE;
-
-    Document* importedDocument() const;
+    // Corresponds to pixel density of the device where this Page is
+    // being displayed. In multi-monitor setups this can vary between pages.
+    // This value does not account for Page zoom, use Frame::devicePixelRatio instead.
+    float deviceScaleFactor() const;
 
 private:
-    void clear();
+    explicit FrameHost(Page&);
 
-    HTMLImportChild* m_loader;
+    Page& m_page;
 };
 
-} // namespace WebCore
+}
 
-#endif // LinkImport_h
+#endif // FrameHost_h