Introduce FetchFormDataConsumerHandle.

Source/modules/fetch/FetchBlobDataConsumerHandle.cpp

 // Copyright 2015 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 "modules/fetch/FetchBlobDataConsumerHandle.h"
 
 #include "core/dom/ActiveDOMObject.h"
 #include "core/dom/CrossThreadTask.h"
 #include "core/dom/ExecutionContext.h"
@@ skipping 333 matching lines @@
             , m_reader(reader)
             , m_notifier(client) { }
         ~ReaderImpl() override { }
 
         Result read(void* data, size_t size, Flags flags, size_t* readSize) override
         {
             if (m_readerContext->drained())
                 return Done;
             m_readerContext->ensureStartLoader();
             Result r = m_reader->read(data, size, flags, readSize);
-            if (r != ShouldWait && !(r == Ok && *readSize == 0)) {
+            if (!(size == 0 && (r == Ok || r == ShouldWait))) {
                 // We read non-empty data, so we cannot use the blob data
                 // handle which represents the whole data.
                 m_readerContext->clearBlobDataHandleForDrain();
             }
             return r;
         }
 
         Result beginRead(const void** buffer, Flags flags, size_t* available) override
         {
             if (m_readerContext->drained())
                 return Done;
             m_readerContext->ensureStartLoader();
-            Result r = m_reader->beginRead(buffer, flags, available);
-            if (r != ShouldWait && !(r == Ok && *available == 0)) {
-                // We read non-empty data, so we cannot use the blob data
-                // handle which represents the whole data.
-                m_readerContext->clearBlobDataHandleForDrain();
-            }
-            return r;
+            m_readerContext->clearBlobDataHandleForDrain();
+            return m_reader->beginRead(buffer, flags, available);
         }
 
         Result endRead(size_t readSize) override
         {
             return m_reader->endRead(readSize);
         }
 
         PassRefPtr<BlobDataHandle> drainAsBlobDataHandle(BlobSizePolicy blobSizePolicy) override
         {
             if (!m_readerContext->m_blobDataHandleForDrain)
                 return nullptr;
             if (blobSizePolicy == DisallowBlobWithInvalidSize && m_readerContext->m_blobDataHandleForDrain->size() == kuint64max)
                 return nullptr;
             RefPtr<BlobDataHandle> blobDataHandle = m_readerContext->m_blobDataHandleForDrain;
             m_readerContext->setDrained();
             m_readerContext->clearBlobDataHandleForDrain();
             return blobDataHandle.release();
         }
 
+        PassRefPtr<FormData> drainAsFormData() override
+        {
+            RefPtr<BlobDataHandle> handle = drainAsBlobDataHandle(AllowBlobWithInvalidSize);
+            if (!handle)
+                return nullptr;
+            RefPtr<FormData> formData = FormData::create();
+            formData->appendBlob(handle->uuid(), handle);
+            return formData.release();
+        }
+
     private:
         RefPtr<ReaderContext> m_readerContext;
         OwnPtr<WebDataConsumerHandle::Reader> m_reader;
         NotifyOnReaderCreationHelper m_notifier;
     };
 
     ReaderContext(ExecutionContext* executionContext, PassRefPtr<BlobDataHandle> blobDataHandle, FetchBlobDataConsumerHandle::LoaderFactory* loaderFactory)
         : m_blobDataHandleForDrain(blobDataHandle)
         , m_loaderStarted(false)
         , m_drained(false)
@@ skipping 57 matching lines @@
 
     return adoptPtr(new FetchBlobDataConsumerHandle(executionContext, blobDataHandle, new DefaultLoaderFactory));
 }
 
 FetchDataConsumerHandle::Reader* FetchBlobDataConsumerHandle::obtainReaderInternal(Client* client)
 {
     return m_readerContext->obtainReader(client).leakPtr();
 }
 
 } // namespace blink