Remove flip_y, premultiply_alpha, unmultiply_alpha support in command buffer.

gpu/command_buffer/build_gles2_cmd_buffer.py

Index: gpu/command_buffer/build_gles2_cmd_buffer.py
diff --git a/gpu/command_buffer/build_gles2_cmd_buffer.py b/gpu/command_buffer/build_gles2_cmd_buffer.py
index b4ad241fddc3368ae5721467a1dc5dc6654c56e1..d81504653b7b96de2423c305d48e04230222e85b 100755
--- a/gpu/command_buffer/build_gles2_cmd_buffer.py
+++ b/gpu/command_buffer/build_gles2_cmd_buffer.py
@@ -761,9 +761,6 @@ _NAMED_TYPE_INFO = {
       'GL_TEXTURE_BINDING_2D',
       'GL_TEXTURE_BINDING_CUBE_MAP',
       'GL_UNPACK_ALIGNMENT',
-      'GL_UNPACK_FLIP_Y_CHROMIUM',
-      'GL_UNPACK_PREMULTIPLY_ALPHA_CHROMIUM',
-      'GL_UNPACK_UNPREMULTIPLY_ALPHA_CHROMIUM',
       'GL_BIND_GENERATES_RESOURCE_CHROMIUM',
       # we can add this because we emulate it if the driver does not support it.
       'GL_VERTEX_ARRAY_BINDING_OES',
@@ -1412,9 +1409,6 @@ _NAMED_TYPE_INFO = {
     'valid': [
       'GL_PACK_ALIGNMENT',
       'GL_UNPACK_ALIGNMENT',
-      'GL_UNPACK_FLIP_Y_CHROMIUM',
-      'GL_UNPACK_PREMULTIPLY_ALPHA_CHROMIUM',
-      'GL_UNPACK_UNPREMULTIPLY_ALPHA_CHROMIUM',
     ],
     'valid_es3': [
       'GL_PACK_ROW_LENGTH',