Revert of Explicit control in tools of ANGLE frontend and backend

tools/gpu/gl/angle/GLTestContext_angle.h

 
 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef GLTestContext_angle_DEFINED
 #define GLTestContext_angle_DEFINED
 
 #include "gl/GLTestContext.h"
 
 namespace sk_gpu_test {
 
 /**
- * Creates a GrGLInterface for the current ANGLE GLES Context. Here current means bound in ANGLE's
- * implementation of EGL.
+ * Creates a GrGLInterface for the currently ANGLE GL context currently bound in ANGLE's EGL
+ * implementation.
  */
 const GrGLInterface* CreateANGLEGLInterface();
 
-enum class ANGLEBackend {
-    kD3D9,
-    kD3D11,
-    kOpenGL
-};
+#ifdef SK_BUILD_FOR_WIN
+/** Creates a GLTestContext backed by ANGLE's Direct3D backend. */
+GLTestContext* CreateANGLEDirect3DGLTestContext();
+#endif
 
-enum class ANGLEContextVersion {
-    kES2,
-    kES3
-};
-
-/** Creates a GLTestContext backed by ANGLE. */
-GLTestContext* CreateANGLETestContext(ANGLEBackend, ANGLEContextVersion);
+/** Creates a GLTestContext backed by ANGLE's OpenGL backend. */
+GLTestContext* CreateANGLEOpenGLGLTestContext();
 
 }  // namespace sk_gpu_test
 #endif