Add support for glMapBufferRange. Use glMapBufferRange and glMapBufferSubData.

src/gpu/gl/GrGLDefines.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 
 #ifndef GrGLDefines_DEFINED
@@ skipping 583 matching lines @@
 #define GR_GL_T4F_V4F                            0x2A28
 #define GR_GL_T2F_C4UB_V3F                       0x2A29
 #define GR_GL_T2F_C3F_V3F                        0x2A2A
 #define GR_GL_T2F_N3F_V3F                        0x2A2B
 #define GR_GL_T2F_C4F_N3F_V3F                    0x2A2C
 #define GR_GL_T4F_C4F_N3F_V4F                    0x2A2D
 
 /* Vertex Buffer Object */
 #define GR_GL_WRITE_ONLY                         0x88B9
 #define GR_GL_BUFFER_MAPPED                      0x88BC
+
+#define GR_GL_MAP_READ_BIT                       0x0001
+#define GR_GL_MAP_WRITE_BIT                      0x0002
+#define GR_GL_MAP_INVALIDATE_RANGE_BIT           0x0004
+#define GR_GL_MAP_INVALIDATE_BUFFER_BIT          0x0008
+#define GR_GL_MAP_FLUSH_EXPLICIT_BIT             0x0010
+#define GR_GL_MAP_UNSYNCHRONIZED_BIT             0x0020
+
 /* Read Format */
 #define GR_GL_IMPLEMENTATION_COLOR_READ_TYPE   0x8B9A
 #define GR_GL_IMPLEMENTATION_COLOR_READ_FORMAT 0x8B9B
 
 /* Shader Source */
 #define GR_GL_COMPILE_STATUS                 0x8B81
 #define GR_GL_INFO_LOG_LENGTH                0x8B84
 #define GR_GL_SHADER_SOURCE_LENGTH           0x8B88
 #define GR_GL_SHADER_COMPILER                0x8DFA
 
@@ skipping 268 matching lines @@
 #define GR_GL_ADJACENT_PAIRS                                0x90AE
 #define GR_GL_FIRST_TO_REST                                 0x90AF
 
 //path gen modes
 #define GR_GL_PATH_GEN_MODE                                 0x90B0
 #define GR_GL_PATH_GEN_COEFF                                0x90B1
 #define GR_GL_PATH_GEN_COLOR_FORMAT                         0x90B2
 #define GR_GL_PATH_GEN_COMPONENTS                           0x90B3
 
 #endif