Support using OpenGL ES context on desktop

Support using OpenGL ES context on desktop for unix and Android platforms. This
is mainly useful in development.

Add --gpuAPI flag to gm, dm, bench, bench_pictures and render_pictures. The
possible parameters for the flag are "gl" and "gles".

R=bsalomon@google.com, mtklein@google.com, robertphillips@google.com

Author: kkinnunen@nvidia.com

Review URL: https://codereview.chromium.org/319043005
diff --git a/include/gpu/gl/SkNullGLContext.h b/include/gpu/gl/SkNullGLContext.h
index 02d968e..6c2a1d7 100644
--- a/include/gpu/gl/SkNullGLContext.h
+++ b/include/gpu/gl/SkNullGLContext.h
@@ -20,7 +20,7 @@
     virtual void swapBuffers() const SK_OVERRIDE {};
 
 protected:
-    virtual const GrGLInterface* createGLContext() SK_OVERRIDE;
+    virtual const GrGLInterface* createGLContext(GrGLStandard forcedGpuAPI) SK_OVERRIDE;
 
     virtual void destroyGLContext() SK_OVERRIDE {};
 };