Make DocumentResource to be a subclass of TextResource

BUG=None

Review-Url: https://codereview.chromium.org/2133153002
Cr-Commit-Position: refs/heads/master@{#404625}

third_party/WebKit/Source/core/fetch/DocumentResource.cpp

@@ -38,8 +38,7 @@ DocumentResource* DocumentResource::fetchSVGDocument(FetchRequest& request, Reso
 }
 
 DocumentResource::DocumentResource(const ResourceRequest& request, Type type, const ResourceLoaderOptions& options)
-    : Resource(request, type, options)
-    , m_decoder(TextResourceDecoder::create("application/xml"))
+    : TextResource(request, type, options, "application/xml", String())
 {
     // FIXME: We'll support more types to support HTMLImports.
     ASSERT(type == SVGDocument);
@@ -55,25 +54,12 @@ DEFINE_TRACE(DocumentResource)
     Resource::trace(visitor);
 }
 
-void DocumentResource::setEncoding(const String& chs)
-{
-    m_decoder->setEncoding(chs, TextResourceDecoder::EncodingFromHTTPHeader);
-}
-
-String DocumentResource::encoding() const
-{
-    return m_decoder->encoding().name();
-}
-
 void DocumentResource::checkNotify()
 {
     if (m_data && mimeTypeAllowed()) {
-        StringBuilder decodedText;
-        decodedText.append(m_decoder->decode(m_data->data(), m_data->size()));
-        decodedText.append(m_decoder->flush());
         // We don't need to create a new frame because the new document belongs to the parent UseElement.
         m_document = createDocument(response().url());
-        m_document->setContent(decodedText.toString());
+        m_document->setContent(decodedText());
     }
     Resource::checkNotify();
 }

third_party/WebKit/Source/core/fetch/DocumentResource.h

@@ -25,6 +25,7 @@
 
 #include "core/fetch/Resource.h"
 #include "core/fetch/ResourceClient.h"
+#include "core/fetch/TextResource.h"
 #include "core/html/parser/TextResourceDecoder.h"
 #include "platform/heap/Handle.h"
 #include <memory>
@@ -35,7 +36,7 @@ class Document;
 class FetchRequest;
 class ResourceFetcher;
 
-class CORE_EXPORT DocumentResource final : public Resource {
+class CORE_EXPORT DocumentResource final : public TextResource {
 public:
     using ClientType = ResourceClient;
 
@@ -45,8 +46,6 @@ public:
 
     Document* document() const { return m_document.get(); }
 
-    void setEncoding(const String&) override;
-    String encoding() const override;
     void checkNotify() override;
 
 private:
@@ -66,7 +65,6 @@ private:
     Document* createDocument(const KURL&);
 
     Member<Document> m_document;
-    std::unique_ptr<TextResourceDecoder> m_decoder;
 };
 
 DEFINE_TYPE_CASTS(DocumentResource, Resource, resource, resource->getType() == Resource::SVGDocument, resource.getType() == Resource::SVGDocument);