Implementing FlushMappedBufferRange in GPU 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 e5269ec73c4a22cd1ec0cc4d1265fc4140144ed6..0a0ea590f2808720073fefa8aa3c3d0822355a9a 100755
--- a/gpu/command_buffer/build_gles2_cmd_buffer.py
+++ b/gpu/command_buffer/build_gles2_cmd_buffer.py
@@ -2870,6 +2870,12 @@ _FUNCTION_INFO = {
     'decoder_func': 'DoFlush',
     'trace_level': 1,
   },
+  'FlushMappedBufferRange': {
+    'decoder_func': 'DoFlushMappedBufferRange',
+    'trace_level': 1,
+    'unit_test': False,
+    'unsafe': True,
+  },
   'FramebufferRenderbuffer': {
     'decoder_func': 'DoFramebufferRenderbuffer',
     'gl_test_func': 'glFramebufferRenderbufferEXT',