Add support for Khr_surfaceless_context.

ui/gl/gl_surface_egl.h

Index: ui/gl/gl_surface_egl.h
diff --git a/ui/gl/gl_surface_egl.h b/ui/gl/gl_surface_egl.h
index 68a99af0e06b8a8cff81f5b7b6e51e70fb2a7006..6cdaf5d2620c0614cdecd8b19fed95d3945256a3 100644
--- a/ui/gl/gl_surface_egl.h
+++ b/ui/gl/gl_surface_egl.h
@@ -111,6 +111,32 @@ class GL_EXPORT PbufferGLSurfaceEGL : public GLSurfaceEGL {
   DISALLOW_COPY_AND_ASSIGN(PbufferGLSurfaceEGL);
 };
 
+// SurfacelessEGL is used as Offscreen surface when platform supports
+// KHR_surfaceless_context and GL_OES_surfaceless_context. This would avoid the
+// need to create a dummy EGLsurface in case we render to client API targets.
+class GL_EXPORT SurfacelessEGL : public GLSurfaceEGL {
+ public:
+  explicit SurfacelessEGL(const gfx::Size& size);
+
+  // Implement GLSurface.
+  virtual EGLConfig GetConfig() OVERRIDE;
+  virtual bool Initialize() OVERRIDE;
+  virtual void Destroy() OVERRIDE;
+  virtual bool IsOffscreen() OVERRIDE;
+  virtual bool SwapBuffers() OVERRIDE;
+  virtual gfx::Size GetSize() OVERRIDE;
+  virtual bool Resize(const gfx::Size& size) OVERRIDE;
+  virtual EGLSurface GetHandle() OVERRIDE;
+  virtual void* GetShareHandle() OVERRIDE;
+
+ protected:
+  virtual ~SurfacelessEGL();
+
+ private:
+  gfx::Size size_;
+  DISALLOW_COPY_AND_ASSIGN(SurfacelessEGL);
+};
+
 }  // namespace gfx
 
 #endif  // UI_GL_GL_SURFACE_EGL_H_