Better handle reentrancy into DocumentLoader::dataReceived().

Source/core/loader/DocumentLoader.h

Index: Source/core/loader/DocumentLoader.h
diff --git a/Source/core/loader/DocumentLoader.h b/Source/core/loader/DocumentLoader.h
index c11c3d0f9ea6392b0c99027618474cb2059b753a..6a5bafc6740ccaac4fc6f078c097dd3e56293f8b 100644
--- a/Source/core/loader/DocumentLoader.h
+++ b/Source/core/loader/DocumentLoader.h
@@ -42,6 +42,7 @@
 #include "core/loader/DocumentWriter.h"
 #include "core/loader/FrameLoaderTypes.h"
 #include "core/loader/NavigationPolicy.h"
+#include "platform/SharedBuffer.h"
 #include "platform/network/ResourceError.h"
 #include "platform/network/ResourceRequest.h"
 #include "platform/network/ResourceResponse.h"
@@ -177,6 +178,7 @@ private:
     void updateRequest(Resource*, const ResourceRequest&) final;
     void responseReceived(Resource*, const ResourceResponse&, PassOwnPtr<WebDataConsumerHandle>) final;
     void dataReceived(Resource*, const char* data, unsigned length) final;
+    void processData(const char* data, unsigned length);
     void notifyFinished(Resource*) final;
 
     bool maybeLoadEmpty();
@@ -233,6 +235,10 @@ private:
         MainResourceDone
     };
     State m_state;
+
+    // Used to protect against reentrancy into dataReceived().
+    bool m_inDataReceived;
+    RefPtr<SharedBuffer> m_dataBuffer;
 };
 
 DECLARE_WEAK_IDENTIFIER_MAP(DocumentLoader);