Use lowercase windows.h in includes to fix Windows cross compilation using mingw.

src/utils/win/SkIStream.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #define WIN32_LEAN_AND_MEAN
-#include <Windows.h>
+#include <windows.h>
 #include <ole2.h>
 #include "SkIStream.h"
 #include "SkStream.h"
 
 /**
  * SkBaseIStream
  */
 SkBaseIStream::SkBaseIStream() : _refcount(1) { }
 SkBaseIStream::~SkBaseIStream() { }
 
@@ skipping 246 matching lines @@
     if (0 == (grfStatFlag & STATFLAG_NONAME)) {
         return STG_E_INVALIDFLAG;
     }
     pStatstg->pwcsName = NULL;
     pStatstg->cbSize.QuadPart = 0;
     pStatstg->clsid = CLSID_NULL;
     pStatstg->type = STGTY_STREAM;
     pStatstg->grfMode = STGM_WRITE;
     return S_OK;
 }