Add miniz library to third_party, use it on Windows

src/core/SkFlate.cpp

Index: src/core/SkFlate.cpp
diff --git a/src/core/SkFlate.cpp b/src/core/SkFlate.cpp
index 2b4e36d7271ea99fe11e8ac2b302d5b8fed4f28a..d633e6389fbae46cb82e69fe1fc42ce67bb4d10c 100644
--- a/src/core/SkFlate.cpp
+++ b/src/core/SkFlate.cpp
@@ -11,7 +11,7 @@
 #include "SkFlate.h"
 #include "SkStream.h"
 
-#ifndef SK_HAS_ZLIB
+#if !defined(SK_HAS_ZLIB) && !defined(MINIZ_INCLUDE)
 bool SkFlate::HaveFlate() { return false; }
 bool SkFlate::Deflate(SkStream*, SkWStream*) { return false; }
 bool SkFlate::Deflate(const void*, size_t, SkWStream*) { return false; }
@@ -26,7 +26,9 @@ bool SkFlate::HaveFlate() {
 
 namespace {
 
-#ifdef SK_SYSTEM_ZLIB
+#ifdef MINIZ_INCLUDE
+#include MINIZ_INCLUDE
+#elif defined(SK_SYSTEM_ZLIB)
 #include <zlib.h>
 #else
 #include SK_ZLIB_INCLUDE