Add a new QUIC platform API quic_aligned.h for the alignment macro definitions.

net/quic/core/quic_types.h

Index: net/quic/core/quic_types.h
diff --git a/net/quic/core/quic_types.h b/net/quic/core/quic_types.h
index b11d2c4e4e77ca255064f25449dd8c0f6a1708b9..30fefd2137e69b831d471fcd4bab9c4c38eaebd3 100644
--- a/net/quic/core/quic_types.h
+++ b/net/quic/core/quic_types.h
@@ -14,16 +14,6 @@
 #include "net/quic/core/quic_time.h"
 #include "net/quic/platform/api/quic_export.h"
 
-#ifdef _MSC_VER
-// MSVC 2013 and prior don't have alignof or aligned(); they have __alignof and
-// a __declspec instead.
-#define QUIC_ALIGN_OF __alignof
-#define QUIC_ALIGNED(X) __declspec(align(X))
-#else
-#define QUIC_ALIGN_OF alignof
-#define QUIC_ALIGNED(X) __attribute__((aligned(X)))
-#endif  // _MSC_VER
-
 namespace net {
 
 typedef uint8_t QuicPathId;