Update gl2.h and update entry points.

Some method signatures were updated. Types like GLclampf and GLvoid
were replaced with other equivalents.

BUG=angleproject:1309

Change-Id: I05e8e2072c5a063d87ad96a855b907424661e680
Reviewed-on: https://chromium-review.googlesource.com/475011
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libANGLE/renderer/FramebufferImpl.h b/src/libANGLE/renderer/FramebufferImpl.h
index 67b2d95..3686495 100644
--- a/src/libANGLE/renderer/FramebufferImpl.h
+++ b/src/libANGLE/renderer/FramebufferImpl.h
@@ -63,7 +63,7 @@
                                  const gl::Rectangle &area,
                                  GLenum format,
                                  GLenum type,
-                                 GLvoid *pixels) const = 0;
+                                 void *pixels) const = 0;
 
     virtual gl::Error blit(ContextImpl *context,
                            const gl::Rectangle &sourceArea,