Revert of Import functionality for new GL backend

src/gpu/gl/GrGLDefines.h

Index: src/gpu/gl/GrGLDefines.h
diff --git a/src/gpu/gl/GrGLDefines.h b/src/gpu/gl/GrGLDefines.h
index cc588b93b77fd965e87be7890a6b673a1a718296..c08c582b71c1c4cba079f1670607c1850d288d4a 100644
--- a/src/gpu/gl/GrGLDefines.h
+++ b/src/gpu/gl/GrGLDefines.h
@@ -889,43 +889,4 @@
 #define GR_GL_MULTISAMPLE_RASTERIZATION_ALLOWED             0x932B
 #define GR_GL_EFFECTIVE_RASTER_SAMPLES                      0x932C
 
-/* GL_KHR_debug */
-#define GR_GL_DEBUG_OUTPUT                                  0x92E0
-#define GR_GL_DEBUG_OUTPUT_SYNCHRONOUS                      0x8242
-#define GR_GL_CONTEXT_FLAG_DEBUG_BIT                        0x00000002
-#define GR_GL_MAX_DEBUG_MESSAGE_LENGTH                      0x9143
-#define GR_GL_MAX_DEBUG_LOGGED_MESSAGES                     0x9144
-#define GR_GL_DEBUG_LOGGED_MESSAGES                         0x9145
-#define GR_GL_DEBUG_NEXT_LOGGED_MESSAGE_LENGTH              0x8243
-#define GR_GL_MAX_DEBUG_GROUP_STACK_DEPTH                   0x826C
-#define GR_GL_DEBUG_GROUP_STACK_DEPTH                       0x826D
-#define GR_GL_MAX_LABEL_LENGTH                              0x82E8
-#define GR_GL_DEBUG_SOURCE_API                              0x8246
-#define GR_GL_DEBUG_SOURCE_WINDOW_SYSTEM                    0x8247
-#define GR_GL_DEBUG_SOURCE_SHADER_COMPILER                  0x8248
-#define GR_GL_DEBUG_SOURCE_THIRD_PARTY                      0x8249
-#define GR_GL_DEBUG_SOURCE_APPLICATION                      0x824A
-#define GR_GL_DEBUG_SOURCE_OTHER                            0x824B
-#define GR_GL_DEBUG_TYPE_ERROR                              0x824C
-#define GR_GL_DEBUG_TYPE_DEPRECATED_BEHAVIOR                0x824D
-#define GR_GL_DEBUG_TYPE_UNDEFINED_BEHAVIOR                 0x824E
-#define GR_GL_DEBUG_TYPE_PORTABILITY                        0x824F
-#define GR_GL_DEBUG_TYPE_PERFORMANCE                        0x8250
-#define GR_GL_DEBUG_TYPE_OTHER                              0x8251
-#define GR_GL_DEBUG_TYPE_MARKER                             0x8268
-#define GR_GL_DEBUG_TYPE_PUSH_GROUP                         0x8269
-#define GR_GL_DEBUG_TYPE_POP_GROUP                          0x826A
-#define GR_GL_DEBUG_SEVERITY_HIGH                           0x9146
-#define GR_GL_DEBUG_SEVERITY_MEDIUM                         0x9147
-#define GR_GL_DEBUG_SEVERITY_LOW                            0x9148
-#define GR_GL_DEBUG_SEVERITY_NOTIFICATION                   0x826B
-#define GR_GL_STACK_UNDERFLOW                               0x0504
-#define GR_GL_STACK_OVERFLOW                                0x0503
-#define GR_GL_BUFFER                                        0x82E0
-#define GR_GL_SHADER                                        0x82E1
-#define GR_GL_PROGRAM                                       0x82E2
-#define GR_GL_QUERY                                         0x82E3
-#define GR_GL_PROGRAM_PIPELINE                              0x82E4
-#define GR_GL_SAMPLER                                       0x82E6
-
 #endif