Enable init'ed but unused var warning on windows for closer parity with mac/linux warnings.

src/utils/win/SkWGL_win.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.
  */
 
 #include "SkWGL.h"
 
@@ skipping 313 matching lines @@
         if (SetPixelFormat(dc, formatToTry, &pfd)) {
             format = formatToTry;
         }
     }
 
     if (0 == format) {
         // Either MSAA wasn't requested or creation failed
         unsigned int num;
         extensions.choosePixelFormat(dc, iAttrs, fAttrs, 1, &format, &num);
         DescribePixelFormat(dc, format, sizeof(pfd), &pfd);
-        BOOL set = SetPixelFormat(dc, format, &pfd);
+        SkDEBUGCODE(BOOL set =) SetPixelFormat(dc, format, &pfd);
         SkASSERT(TRUE == set);
     }
 
     HGLRC glrc = NULL;
     if (preferCoreProfile && extensions.hasExtension(dc, "WGL_ARB_create_context")) {
         static const int kCoreGLVersions[] = {
             4, 3,
             4, 2,
             4, 1,
             4, 0,
@@ skipping 17 matching lines @@
     }
 
     if (NULL == glrc) {
         glrc = wglCreateContext(dc);
     }
     SkASSERT(glrc);
 
     wglMakeCurrent(prevDC, prevGLRC);
     return glrc;
 }