Refactor Android includes.

Forward declare ANativeWindow, and remove <hardware/gralloc.h> where
GrallocAndroid.hpp already includes it.

Change-Id: Idebd4c40280960ff00cd51b6633c1c84a8cf7de2
Reviewed-on: https://swiftshader-review.googlesource.com/11288
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>

src/Main/FrameBufferAndroid.hpp

diff --git a/src/Main/FrameBufferAndroid.hpp b/src/Main/FrameBufferAndroid.hpp
index 7e34ea2..4400188 100644
--- a/src/Main/FrameBufferAndroid.hpp
+++ b/src/Main/FrameBufferAndroid.hpp
@@ -18,8 +18,8 @@
 #include "Main/FrameBuffer.hpp"
 #include "Common/Debug.hpp"
 
-#include <hardware/gralloc.h>
-#include <system/window.h>
+struct ANativeWindow;
+struct ANativeWindowBuffer;
 
 namespace sw
 {