Split pixelBuffer from pack/unpack state

This will refactor will help use packed enums for buffer targets.

BUG=angleproject:2169

Change-Id: Ie7ed3e105f89457c67027e6598d7e29503ad355c
Reviewed-on: https://chromium-review.googlesource.com/745181
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libANGLE/renderer/renderer_utils.h b/src/libANGLE/renderer/renderer_utils.h
index ca2b446..5a1cb38 100644
--- a/src/libANGLE/renderer/renderer_utils.h
+++ b/src/libANGLE/renderer/renderer_utils.h
@@ -138,7 +138,7 @@
     const Entry *mData;
 };
 
-struct PackPixelsParams : private angle::NonCopyable
+struct PackPixelsParams
 {
     PackPixelsParams();
     PackPixelsParams(const gl::Rectangle &area,
@@ -146,8 +146,8 @@
                      GLenum type,
                      GLuint outputPitch,
                      const gl::PixelPackState &pack,
+                     gl::Buffer *packBufferIn,
                      ptrdiff_t offset);
-    PackPixelsParams(const gl::Context *context, const PackPixelsParams &other);
 
     gl::Rectangle area;
     GLenum format;