Remove the compile-time selection of the GL implementation based on the
GR_SUPPORT_GLDESKTOP family of macros.  

Support for the platform is configured dynamically, by querying the
fBindingsExported member of active GrGLInterface instance.

Review: http://codereview.appspot.com/4298048/ 



git-svn-id: http://skia.googlecode.com/svn/trunk@960 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/include/GrGLInterface.h b/gpu/include/GrGLInterface.h
index 7bee111..7a44f4f 100644
--- a/gpu/include/GrGLInterface.h
+++ b/gpu/include/GrGLInterface.h
@@ -63,6 +63,12 @@
 typedef double GrGLclampd;
 typedef void GrGLvoid;
 
+enum GrGLBinding {
+    kDesktop_GrGLBinding = 0x01,
+    kES1_GrGLBinding = 0x02,
+    kES2_GrGLBinding = 0x04
+};
+
 extern "C" {
 /*
  * The following interface exports the OpenGL entry points used by the system.
@@ -178,6 +184,10 @@
     typedef GrGLvoid* (GR_GL_FUNCTION_TYPE *GrGLMapBufferProc)(GrGLenum target, GrGLenum access);
     typedef GrGLboolean (GR_GL_FUNCTION_TYPE *GrGLUnmapBufferProc)(GrGLenum target);
 
+    // Indicator variable specifying the type of GL implementation
+    // exported:  GLES{1|2} or Desktop.
+    GrGLBinding fBindingsExported;
+
     GrGLActiveTextureProc fActiveTexture;
     GrGLAttachShaderProc fAttachShader;
     GrGLBindAttribLocationProc fBindAttribLocation;