Completely removed the Extensions3D class (Take 2)

Source/platform/graphics/GraphicsTypes3D.h

Index: Source/platform/graphics/GraphicsTypes3D.h
diff --git a/Source/platform/graphics/GraphicsTypes3D.h b/Source/platform/graphics/GraphicsTypes3D.h
index 1cacc5b3b9be97635b00dcc36f5ac49cda20ad08..6fd3e575b5a01dd884942d6bee0db2d5fbc36070 100644
--- a/Source/platform/graphics/GraphicsTypes3D.h
+++ b/Source/platform/graphics/GraphicsTypes3D.h
@@ -39,4 +39,16 @@ const unsigned GC3D_CONTEXT_LOST_WEBGL = 0x9242;
 const unsigned GC3D_UNPACK_COLORSPACE_CONVERSION_WEBGL = 0x9243;
 const unsigned GC3D_BROWSER_DEFAULT_WEBGL = 0x9244;
 
+// GL_CHROMIUM_flipy
+const unsigned GC3D_UNPACK_FLIP_Y_CHROMIUM = 0x9240;
+
+// GL_CHROMIUM_copy_texture
+const unsigned GC3D_UNPACK_PREMULTIPLY_ALPHA_CHROMIUM = 0x9241;
+const unsigned GC3D_UNPACK_UNPREMULTIPLY_ALPHA_CHROMIUM = 0x9242;
+
+// GL_AMD_compressed_ATC_texture
+const unsigned GC3D_COMPRESSED_ATC_RGB_AMD = 0x8C92;
+const unsigned GC3D_COMPRESSED_ATC_RGBA_EXPLICIT_ALPHA_AMD = 0x8C93;
+const unsigned GC3D_COMPRESSED_ATC_RGBA_INTERPOLATED_ALPHA_AMD = 0x87EE;
+
 #endif