Extract tree root responsibility out of HTMLImportsController.

The HTMLImportsController wishes to become more of an Actor-style object,
and it being a root of the import tree leads to ambiguities in responsibilities.
So we should split these responsibilities cleanly.

R=morrita
BUG=

Review URL: https://codereview.chromium.org/301803002

git-svn-id: svn://svn.chromium.org/blink/trunk@175108 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/core.gypi

@@ -2685,6 +2685,8 @@
             'html/imports/HTMLImportState.h',
             'html/imports/HTMLImportStateResolver.cpp',
             'html/imports/HTMLImportStateResolver.h',
+            'html/imports/HTMLImportTreeRoot.cpp',
+            'html/imports/HTMLImportTreeRoot.h',
             'html/imports/HTMLImportsController.cpp',
             'html/imports/HTMLImportsController.h',
             'html/imports/LinkImport.cpp',

third_party/WebKit/Source/core/html/imports/HTMLImport.h

@@ -51,13 +51,15 @@ class KURL;
 //
 // HTML Imports form a tree:
 //
-// * The root of the tree is HTMLImportsController, which is owned by the master
+// * The root of the tree is HTMLImportTreeRoot.
+//
+// * The HTMLImportTreeRoot is owned HTMLImportsController, which is owned by the master
 //   document as a DocumentSupplement.
 //
-// * The non-root nodes are HTMLImportChild, which is owned by LinkStyle, that is owned by HTMLLinkElement.
+// * The non-root nodes are HTMLImportChild. They are also owned by HTMLImportsController.
 //   LinkStyle is wired into HTMLImportChild by implementing HTMLImportChildClient interface
 //
-// * Both HTMLImportsController and HTMLImportChild are derived from HTMLImport superclass
+// * Both HTMLImportTreeRoot and HTMLImportChild are derived from HTMLImport superclass
 //   that models the tree data structure using WTF::TreeNode and provides a set of
 //   virtual functions.
 //
@@ -65,12 +67,6 @@ class KURL;
 // One assumption is that the tree is append-only and nodes are never inserted in the middle of the tree nor removed.
 //
 //
-//    HTMLImport <|- HTMLImportsController <- Document
-//                   *
-//                   |
-//               <|- HTMLImportChild <- LinkStyle <- HTMLLinkElement
-//
-//
 // # Import Sharing and HTMLImportLoader
 //
 // The HTML Imports spec calls for de-dup mechanism to share already loaded imports.
@@ -94,7 +90,7 @@ class KURL;
 //   In such case, the preceding import should be loaded and following ones should be de-duped.
 //
 
-// The superclass of HTMLImportsController and HTMLImportChild
+// The superclass of HTMLImportTreeRoot and HTMLImportChild
 // This represents the import tree data structure.
 class HTMLImport : public TreeNode<HTMLImport> {
 public:
@@ -105,6 +101,7 @@ public:
 
     virtual ~HTMLImport() { }
 
+    // FIXME: Consider returning HTMLImportTreeRoot.
     HTMLImport* root();
     bool precedes(HTMLImport*);
     bool isRoot() const { return !isChild(); }

third_party/WebKit/Source/core/html/imports/HTMLImportChild.cpp

@@ -38,6 +38,7 @@
 #include "core/dom/custom/CustomElementMicrotaskQueue.h"
 #include "core/html/imports/HTMLImportChildClient.h"
 #include "core/html/imports/HTMLImportLoader.h"
+#include "core/html/imports/HTMLImportTreeRoot.h"
 #include "core/html/imports/HTMLImportsController.h"
 
 namespace WebCore {
@@ -124,7 +125,7 @@ Document* HTMLImportChild::document() const
 
 void HTMLImportChild::stateWillChange()
 {
-    toHTMLImportsController(root())->scheduleRecalcState();
+    toHTMLImportTreeRoot(root())->scheduleRecalcState();
 }
 
 void HTMLImportChild::stateDidChange()

third_party/WebKit/Source/core/html/imports/HTMLImportTreeRoot.cpp

+// Copyright 2014 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.
+
+#include "config.h"
+#include "core/html/imports/HTMLImportTreeRoot.h"
+
+#include "core/dom/Document.h"
+#include "core/dom/StyleEngine.h"
+#include "core/frame/LocalFrame.h"
+
+namespace WebCore {
+
+PassOwnPtr<HTMLImportTreeRoot> HTMLImportTreeRoot::create(Document* document)
+{
+    return adoptPtr(new HTMLImportTreeRoot(document));
+}
+
+HTMLImportTreeRoot::HTMLImportTreeRoot(Document* document)
+    : HTMLImport(HTMLImport::Sync)
+    , m_document(document)
+    , m_recalcTimer(this, &HTMLImportTreeRoot::recalcTimerFired)
+{
+    recalcTreeState(this); // This recomputes initial state.
+}
+
+Document* HTMLImportTreeRoot::document() const
+{
+    return m_document;
+}
+
+bool HTMLImportTreeRoot::isDone() const
+{
+    return !m_document->parsing() && m_document->styleEngine()->haveStylesheetsLoaded();
+}
+
+void HTMLImportTreeRoot::stateWillChange()
+{
+    scheduleRecalcState();
+}
+
+void HTMLImportTreeRoot::stateDidChange()
+{
+    HTMLImport::stateDidChange();
+
+    if (!state().isReady())
+        return;
+    if (LocalFrame* frame = m_document->frame())
+        frame->loader().checkCompleted();
+}
+
+void HTMLImportTreeRoot::scheduleRecalcState()
+{
+    if (m_recalcTimer.isActive() || !m_document)
+        return;
+    m_recalcTimer.startOneShot(0, FROM_HERE);
+}
+
+void HTMLImportTreeRoot::recalcTimerFired(Timer<HTMLImportTreeRoot>*)
+{
+    ASSERT(m_document);
+
+    do {
+        m_recalcTimer.stop();
+        HTMLImport::recalcTreeState(this);
+    } while (m_recalcTimer.isActive());
+}
+
+}

third_party/WebKit/Source/core/html/imports/HTMLImportTreeRoot.h

+// Copyright 2014 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 HTMLImportTreeRoot_h
+#define HTMLImportTreeRoot_h
+
+#include "core/html/imports/HTMLImport.h"
+#include "platform/Timer.h"
+#include "wtf/PassOwnPtr.h"
+
+namespace WebCore {
+
+class HTMLImportTreeRoot : public HTMLImport {
+public:
+    static PassOwnPtr<HTMLImportTreeRoot> create(Document*);
+
+    // HTMLImport
+    virtual Document* document() const OVERRIDE;
+    virtual bool isDone() const OVERRIDE;
+    virtual void stateWillChange() OVERRIDE;
+    virtual void stateDidChange() OVERRIDE;
+
+    void scheduleRecalcState();
+
+private:
+    explicit HTMLImportTreeRoot(Document*);
+
+    void recalcTimerFired(Timer<HTMLImportTreeRoot>*);
+
+    Document* m_document;
+    Timer<HTMLImportTreeRoot> m_recalcTimer;
+};
+
+DEFINE_TYPE_CASTS(HTMLImportTreeRoot, HTMLImport, import, import->isRoot(), import.isRoot());
+
+}
+
+#endif

third_party/WebKit/Source/core/html/imports/HTMLImportsController.cpp

@@ -32,12 +32,12 @@
 #include "core/html/imports/HTMLImportsController.h"
 
 #include "core/dom/Document.h"
-#include "core/dom/StyleEngine.h"
 #include "core/fetch/ResourceFetcher.h"
 #include "core/frame/LocalFrame.h"
 #include "core/html/imports/HTMLImportChild.h"
 #include "core/html/imports/HTMLImportChildClient.h"
 #include "core/html/imports/HTMLImportLoader.h"
+#include "core/html/imports/HTMLImportTreeRoot.h"
 
 namespace WebCore {
 
@@ -50,11 +50,9 @@ void HTMLImportsController::provideTo(Document& master)
 }
 
 HTMLImportsController::HTMLImportsController(Document& master)
-    : HTMLImport(HTMLImport::Sync)
-    , m_master(&master)
-    , m_recalcTimer(this, &HTMLImportsController::recalcTimerFired)
+    : m_master(&master)
+    , m_root(HTMLImportTreeRoot::create(&master))
 {
-    recalcTreeState(this); // This recomputes initial state.
 }
 
 HTMLImportsController::~HTMLImportsController()
@@ -76,7 +74,7 @@ void HTMLImportsController::clear()
         m_master->setImportsController(0);
     m_master = 0;
 
-    m_recalcTimer.stop();
+    m_root.clear();
 }
 
 static bool makesCycle(HTMLImport* parent, const KURL& url)
@@ -103,7 +101,7 @@ HTMLImportChild* HTMLImportsController::createChild(const KURL& url, HTMLImportL
 HTMLImportChild* HTMLImportsController::load(HTMLImport* parent, HTMLImportChildClient* client, FetchRequest request)
 {
     ASSERT(!request.url().isEmpty() && request.url().isValid());
-    ASSERT(parent == this || toHTMLImportChild(parent)->loader()->isFirstImport(toHTMLImportChild(parent)));
+    ASSERT(parent == root() || toHTMLImportChild(parent)->loader()->isFirstImport(toHTMLImportChild(parent)));
 
     if (HTMLImportChild* childToShareWith = findLinkFor(request.url())) {
         HTMLImportLoader* loader = childToShareWith->loader();
@@ -162,17 +160,12 @@ LocalFrame* HTMLImportsController::frame() const
     return m_master->frame();
 }
 
-Document* HTMLImportsController::document() const
-{
-    return m_master;
-}
-
 bool HTMLImportsController::shouldBlockScriptExecution(const Document& document) const
 {
     ASSERT(document.importsController() == this);
     if (HTMLImportLoader* loader = loaderFor(document))
         return loader->shouldBlockScriptExecution();
-    return state().shouldBlockScriptExecution();
+    return root()->state().shouldBlockScriptExecution();
 }
 
 void HTMLImportsController::wasDetachedFrom(const Document& document)
@@ -182,43 +175,6 @@ void HTMLImportsController::wasDetachedFrom(const Document& document)
         clear();
 }
 
-bool HTMLImportsController::isDone() const
-{
-    return !m_master->parsing() && m_master->styleEngine()->haveStylesheetsLoaded();
-}
-
-void HTMLImportsController::stateWillChange()
-{
-    scheduleRecalcState();
-}
-
-void HTMLImportsController::stateDidChange()
-{
-    HTMLImport::stateDidChange();
-
-    if (!state().isReady())
-        return;
-    if (LocalFrame* frame = m_master->frame())
-        frame->loader().checkCompleted();
-}
-
-void HTMLImportsController::scheduleRecalcState()
-{
-    if (m_recalcTimer.isActive() || !m_master)
-        return;
-    m_recalcTimer.startOneShot(0, FROM_HERE);
-}
-
-void HTMLImportsController::recalcTimerFired(Timer<HTMLImportsController>*)
-{
-    ASSERT(m_master);
-
-    do {
-        m_recalcTimer.stop();
-        HTMLImport::recalcTreeState(this);
-    } while (m_recalcTimer.isActive());
-}
-
 HTMLImportLoader* HTMLImportsController::createLoader()
 {
     m_loaders.append(HTMLImportLoader::create(this));

third_party/WebKit/Source/core/html/imports/HTMLImportsController.h

@@ -48,8 +48,9 @@ class ResourceFetcher;
 class HTMLImportChild;
 class HTMLImportChildClient;
 class HTMLImportLoader;
+class HTMLImportTreeRoot;
 
-class HTMLImportsController FINAL : public NoBaseWillBeGarbageCollectedFinalized<HTMLImportsController>, public HTMLImport, public DocumentSupplement {
+class HTMLImportsController FINAL : public NoBaseWillBeGarbageCollectedFinalized<HTMLImportsController>, public DocumentSupplement {
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(HTMLImportsController);
     WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED;
 public:
@@ -58,16 +59,12 @@ public:
     explicit HTMLImportsController(Document&);
     virtual ~HTMLImportsController();
 
+    HTMLImportTreeRoot* root() const { return m_root.get(); }
+
     bool isMaster(const Document& document) const { return m_master == &document; }
     bool shouldBlockScriptExecution(const Document&) const;
     void wasDetachedFrom(const Document&);
 
-    // HTMLImport
-    virtual Document* document() const OVERRIDE;
-    virtual bool isDone() const OVERRIDE;
-    virtual void stateWillChange() OVERRIDE;
-    virtual void stateDidChange() OVERRIDE;
-
     HTMLImportChild* load(HTMLImport* parent, HTMLImportChildClient*, FetchRequest);
     void showSecurityErrorMessage(const String&);
 
@@ -76,7 +73,6 @@ public:
     LocalFrame* frame() const;
     Document* master() const { return m_master; }
 
-    void recalcTimerFired(Timer<HTMLImportsController>*);
 
     HTMLImportLoader* createLoader();
 
@@ -84,7 +80,6 @@ public:
     HTMLImportLoader* loaderAt(size_t i) const { return m_loaders[i].get(); }
     HTMLImportLoader* loaderFor(const Document&) const;
 
-    void scheduleRecalcState();
     HTMLImportChild* findLinkFor(const KURL&) const;
 
 private:
@@ -92,7 +87,8 @@ private:
     void clear();
 
     Document* m_master;
-    Timer<HTMLImportsController> m_recalcTimer;
+
+    OwnPtr<HTMLImportTreeRoot> m_root;
 
     // List of import which has been loaded or being loaded.
     typedef Vector<OwnPtr<HTMLImportChild> > ImportList;
@@ -102,8 +98,6 @@ private:
     LoaderList m_loaders;
 };
 
-DEFINE_TYPE_CASTS(HTMLImportsController, HTMLImport, import, import->isRoot(), import.isRoot());
-
 } // namespace WebCore
 
 #endif // HTMLImportsController_h

third_party/WebKit/Source/core/html/imports/LinkImport.cpp

@@ -36,9 +36,9 @@
 #include "core/html/HTMLLinkElement.h"
 #include "core/html/imports/HTMLImportChild.h"
 #include "core/html/imports/HTMLImportLoader.h"
+#include "core/html/imports/HTMLImportTreeRoot.h"
 #include "core/html/imports/HTMLImportsController.h"
 
-
 namespace WebCore {
 
 PassOwnPtrWillBeRawPtr<LinkImport> LinkImport::create(HTMLLinkElement* owner)
@@ -89,7 +89,7 @@ void LinkImport::process()
 
     HTMLImportsController* controller = m_owner->document().importsController();
     HTMLImportLoader* loader = m_owner->document().importLoader();
-    HTMLImport* parent = loader ? static_cast<HTMLImport*>(loader->firstImport()) : static_cast<HTMLImport*>(controller);
+    HTMLImport* parent = loader ? static_cast<HTMLImport*>(loader->firstImport()) : static_cast<HTMLImport*>(controller->root());
     m_child = controller->load(parent, this, builder.build(true));
     if (!m_child) {
         didFinish();