Add support for GL_CHROMIUM_pixel_transfer_buffer_object.

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 927764b67a4d76d6977e2bc014e8f3faa4f1bf2d..1ee0001f35e92b35aa47ef6444c04564abd53e66 100755
--- a/gpu/command_buffer/build_gles2_cmd_buffer.py
+++ b/gpu/command_buffer/build_gles2_cmd_buffer.py
@@ -1157,6 +1157,7 @@ _FUNCTION_INFO = {
     'type': 'Bind',
     'decoder_func': 'DoBindBuffer',
     'gen_func': 'GenBuffersARB',
+    'impl_func': False,
   },
   'BindFramebuffer': {
     'type': 'Bind',
@@ -1723,6 +1724,13 @@ _FUNCTION_INFO = {
     'decoder_func': 'DoLinkProgram',
     'impl_func':  False,
   },
+  'MapBufferCHROMIUM': {
+    'gen_cmd': False,
+    'extension': True,
+    'chromium': True,
+    'client_test': False,
+    'chromium': True,
+  },
   'MapBufferSubDataCHROMIUM': {
     'gen_cmd': False,
     'extension': True,
@@ -1945,6 +1953,13 @@ _FUNCTION_INFO = {
     'count': 16,
     'decoder_func': 'DoUniformMatrix4fv',
   },
+  'UnmapBufferCHROMIUM': {
+    'gen_cmd': False,
+    'extension': True,
+    'chromium': True,
+    'client_test': False,
+    'chromium': True,
+  },
   'UnmapBufferSubDataCHROMIUM': {
     'gen_cmd': False,
     'extension': True,