add/fix copyrights

src/opts/SkXfermode_opts_arm_neon.cpp

-// Copyright 2013 unknown
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
 
 #include "SkXfermode.h"
 #include "SkXfermode_proccoeff.h"
 #include "SkColorPriv.h"
 
 #include <arm_neon.h>
 #include "SkColor_opts_neon.h"
 #include "SkXfermode_opts_arm_neon.h"
 #include "Sk4pxXfermode.h"
 
@@ skipping 1007 matching lines @@
     // TODO: Sk4pxXfermode now covers every mode found in this file.  Delete them all!
     if (auto proc = gNEONXfermodeProcs[mode]) {
         return SkNEW_ARGS(SkNEONProcCoeffXfermode, (rec, mode, (void*)proc));
     }
     return NULL;
 }
 
 SkXfermodeProc SkPlatformXfermodeProcFactory_impl_neon(SkXfermode::Mode mode) {
     return gNEONXfermodeProcs1[mode];
 }