Initial version of external_oes texture support and unit test

Committed: https://skia.googlesource.com/skia/+/27a048700778d4cebfc23301d1780649791b0e03

Review URL: https://codereview.chromium.org/1451683002
diff --git a/include/gpu/gl/GrGLFunctions.h b/include/gpu/gl/GrGLFunctions.h
index a8a721e..1086186 100644
--- a/include/gpu/gl/GrGLFunctions.h
+++ b/include/gpu/gl/GrGLFunctions.h
@@ -69,6 +69,7 @@
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLDrawBufferProc)(GrGLenum mode);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLDrawBuffersProc)(GrGLsizei n, const GrGLenum* bufs);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLDrawElementsProc)(GrGLenum mode, GrGLsizei count, GrGLenum type, const GrGLvoid* indices);
+typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLEGLImageTargetTexture2DProc)(GrGLenum target, GrGLeglImage image);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLEnableProc)(GrGLenum cap);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLEnableVertexAttribArrayProc)(GrGLuint index);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLEndQueryProc)(GrGLenum target);
@@ -352,8 +353,8 @@
 /** EGL functions */
 typedef const char* (GR_GL_FUNCTION_TYPE* GrEGLQueryStringProc)(GrEGLDisplay dpy, GrEGLint name);
 typedef GrEGLDisplay (GR_GL_FUNCTION_TYPE* GrEGLGetCurrentDisplayProc)();
-typedef GrEGLImageKHR (GR_GL_FUNCTION_TYPE* GrEGLCreateImageProc)(GrEGLDisplay dpy, GrEGLContext ctx, GrEGLenum target, GrEGLClientBuffer buffer, const GrEGLint *attrib_list);
-typedef GrEGLBoolean (GR_GL_FUNCTION_TYPE* GrEGLDestroyImageProc)(GrEGLDisplay dpy, GrEGLImageKHR image);
+typedef GrEGLImage (GR_GL_FUNCTION_TYPE* GrEGLCreateImageProc)(GrEGLDisplay dpy, GrEGLContext ctx, GrEGLenum target, GrEGLClientBuffer buffer, const GrEGLint *attrib_list);
+typedef GrEGLBoolean (GR_GL_FUNCTION_TYPE* GrEGLDestroyImageProc)(GrEGLDisplay dpy, GrEGLImage image);
 }  // extern "C"
 
 #endif