Adding skia gl interface binding for glCopyTextureCHROMIUM

BUG=415100

Review URL: https://codereview.chromium.org/601883002

Cr-Commit-Position: refs/heads/master@{#296488}

gpu/skia_bindings/gl_bindings_skia_cmd_buffer.cc

@@ -40,6 +40,7 @@ GrGLInterface* CreateCommandBufferSkiaGLBinding() {
   functions->fCompileShader = glCompileShader;
   functions->fCompressedTexImage2D = glCompressedTexImage2D;
   functions->fCopyTexSubImage2D = glCopyTexSubImage2D;
+  functions->fCopyTextureCHROMIUM = glCopyTextureCHROMIUM;
   functions->fCreateProgram = glCreateProgram;
   functions->fCreateShader = glCreateShader;
   functions->fCullFace = glCullFace;