gpu: Add GpuFence framework.

gpu/command_buffer/cmd_buffer_functions.txt

Index: gpu/command_buffer/cmd_buffer_functions.txt
diff --git a/gpu/command_buffer/cmd_buffer_functions.txt b/gpu/command_buffer/cmd_buffer_functions.txt
index 06b4910a65741f34b42c34ade84bf09eba25f2d7..ede8bc48e934858850dbaa9dfc474cb7da6700c2 100644
--- a/gpu/command_buffer/cmd_buffer_functions.txt
+++ b/gpu/command_buffer/cmd_buffer_functions.txt
@@ -277,6 +277,8 @@ GL_APICALL void         GL_APIENTRY glGetUniformsES3CHROMIUM (GLidProgram progra
 GL_APICALL GLuint       GL_APIENTRY glCreateImageCHROMIUM (ClientBuffer buffer, GLsizei width, GLsizei height, GLenum internalformat);
 GL_APICALL void         GL_APIENTRY glDestroyImageCHROMIUM (GLuint image_id);
 GL_APICALL GLuint       GL_APIENTRY glCreateGpuMemoryBufferImageCHROMIUM (GLsizei width, GLsizei height, GLenum internalformat, GLenum usage);
+GL_APICALL GLuint       GL_APIENTRY glCreateFenceCHROMIUM (ClientFence fence);
+GL_APICALL void         GL_APIENTRY glDestroyFenceCHROMIUM (GLuint fence_id);
 GL_APICALL void         GL_APIENTRY glDescheduleUntilFinishedCHROMIUM (void);
 GL_APICALL void         GL_APIENTRY glGetTranslatedShaderSourceANGLE (GLidShader shader, GLsizeiNotNegative bufsize, GLsizeiOptional* length, char* source);
 GL_APICALL void         GL_APIENTRY glPostSubBufferCHROMIUM (GLint x, GLint y, GLint width, GLint height);