Revert 132934 - this change seems to break many webgl related layout tests

gpu/command_buffer/build_gles2_cmd_buffer.py

Index: gpu/command_buffer/build_gles2_cmd_buffer.py
===================================================================
--- gpu/command_buffer/build_gles2_cmd_buffer.py	(revision 132957)
+++ gpu/command_buffer/build_gles2_cmd_buffer.py	(working copy)
@@ -587,8 +587,6 @@
     'valid': [
       'GL_PACK_ALIGNMENT',
       'GL_UNPACK_ALIGNMENT',
-      'GL_UNPACK_FLIP_Y_CHROMIUM',
-      'GL_UNPACK_PREMULTIPLY_ALPHA_CHROMIUM',
     ],
     'invalid': [
       'GL_PACK_SWAP_BYTES',
@@ -1512,9 +1510,6 @@
                   'GLsizei stride, GLuint offset',
       'client_test': False,
   },
-  'Viewport': {
-    'decoder_func': 'DoViewport',
-  },
   'ResizeCHROMIUM': {
       'type': 'Custom',
       'impl_func': False,
@@ -1569,12 +1564,6 @@
     'extension': True,
     'chromium': True,
   },
-  'CopyTextureCHROMIUM': {
-    'decoder_func': 'DoCopyTextureCHROMIUM',
-    'unit_test': False,
-    'extension': True,
-    'chromium': True,
-  },
   'TexStorage2DEXT': {
     'unit_test': False,
     'extension': True,