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

include/utils/SkCondVar.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkCondVar_DEFINED
 #define SkCondVar_DEFINED
 
 #ifdef SK_USE_POSIX_THREADS
 #include <pthread.h>
 #elif defined(SK_BUILD_FOR_WIN32)
-#include <Windows.h>
+#include <windows.h>
 #endif
 
 /**
  * Condition variable for blocking access to shared data from other threads and
  * controlling which threads are awake.
  *
  * Currently only supported on platforms with posix threads and Windows Vista and
  * above.
  */
 class SkCondVar {
@@ skipping 34 matching lines @@
 #ifdef SK_USE_POSIX_THREADS
     pthread_mutex_t  fMutex;
     pthread_cond_t   fCond;
 #elif defined(SK_BUILD_FOR_WIN32)
     CRITICAL_SECTION   fCriticalSection;
     CONDITION_VARIABLE fCondition;
 #endif
 };
 
 #endif