Improve GL bindings for Ganesh surfaces.

mojo/skia/ganesh_framebuffer_surface.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <GLES2/gl2.h>
+
+#include "base/logging.h"
+#include "mojo/skia/ganesh_framebuffer_surface.h"
+
+namespace mojo {
+
+GaneshFramebufferSurface::GaneshFramebufferSurface(GaneshContext* context) {
+  DCHECK(context);
+  GaneshContext::Scope scope(context);
+
+  GLint samples = 0;
+  glGetIntegerv(GL_SAMPLES, &samples);
+  GLint stencil_bits = 0;
+  glGetIntegerv(GL_STENCIL_BITS, &stencil_bits);
+  GLint framebuffer_binding = 0;
+  glGetIntegerv(GL_FRAMEBUFFER_BINDING, &framebuffer_binding);
+  GLint viewport[4] = {0, 0, 0, 0};
+  glGetIntegerv(GL_VIEWPORT, viewport);
+  DCHECK(viewport[2] > 0);
+  DCHECK(viewport[3] > 0);
+
+  GrBackendRenderTargetDesc desc;
+  desc.fWidth = viewport[2];
+  desc.fHeight = viewport[3];
+  desc.fConfig = kSkia8888_GrPixelConfig;
+  desc.fOrigin = kBottomLeft_GrSurfaceOrigin;
+  desc.fSampleCnt = samples;
+  desc.fStencilBits = stencil_bits;
+  desc.fRenderTargetHandle = framebuffer_binding;
+  GrRenderTarget* render_target =
+      context->gr()->textureProvider()->wrapBackendRenderTarget(desc);
+  DCHECK(render_target);
+
+  surface_ = skia::AdoptRef(SkSurface::NewRenderTargetDirect(render_target));
+  DCHECK(surface_);
+}
+
+GaneshFramebufferSurface::~GaneshFramebufferSurface() {}
+
+}  // namespace mojo