Issue 1669 - Report blocked object subrequests as failed, not as empty HTML

src/plugin/PluginWbPassThrough.cpp

 #include "PluginStdAfx.h"
 
 #include "PluginWbPassThrough.h"
 #include "PluginClient.h"
 #include "PluginClientFactory.h"
 #include "PluginFilter.h"
 #include "PluginSettings.h"
 #include "PluginClass.h"
 #include "PluginSystem.h"
 #include <WinInet.h>
@@ skipping 314 matching lines @@
     m_contentType = CFilter::EContentType::contentTypeObjectSubrequest;
   }
 
   if (pszAdditionalHeaders && *pszAdditionalHeaders && IsXmlHttpRequest(*pszAdditionalHeaders))
   {
     m_contentType = CFilter::EContentType::contentTypeXmlHttpRequest;
   }
 
   if (client->ShouldBlock(szURL, m_contentType, m_boundDomain, /*debug flag but must be set*/true))
   {
+    // NOTE: Feeding custom HTML to Flash, instead of original object subrequest
+    // doesn't have much sense. It also can manifest in unwanted result 
+    // like video being blocked (See https://issues.adblockplus.org/ticket/1669)        
+    // So we report blocked object subrequests as failed, not just empty HTML.
     m_isCustomResponse = m_contentType != CFilter::contentTypeObjectSubrequest; 
     return E_ABORT;
   }
   return nativeHr;
 }
 
 STDMETHODIMP WBPassthruSink::OnResponse(DWORD dwResponseCode, LPCWSTR szResponseHeaders, LPCWSTR szRequestHeaders, LPWSTR *pszAdditionalRequestHeaders)
 {
   if (pszAdditionalRequestHeaders)
   {
@@ skipping 39 matching lines @@
   }
 
   return OnStart(szUrl, pOIProtSink, pOIBindInfo, grfPI, dwReserved, m_spInternetProtocol);
 }
 
 STDMETHODIMP WBPassthru::Read(/* [in, out] */ void *pv,/* [in] */ ULONG cb,/* [out] */ ULONG *pcbRead)
 {
   WBPassthruSink* pSink = GetSink();
   return pSink->OnRead(pv, cb, pcbRead);
 }