Ozone: Keep the native pixmap alive till gl_image is destroyed

ui/gl/gl_image_ozone_native_pixmap.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 "ui/gl/gl_image_ozone_native_pixmap.h"
 
 #define FOURCC(a, b, c, d)                                    \
   ((static_cast<uint32>(a)) | (static_cast<uint32>(b) << 8) | \
    (static_cast<uint32>(c) << 16) | (static_cast<uint32>(d) << 24))
 
@@ skipping 57 matching lines @@
   return 0;
 }
 
 }  // namespace
 
 GLImageOzoneNativePixmap::GLImageOzoneNativePixmap(const Size& size,
                                                    unsigned internalformat)
     : GLImageEGL(size), internalformat_(internalformat) {}
 
 GLImageOzoneNativePixmap::~GLImageOzoneNativePixmap() {
-  DCHECK(!pixmap_);
 }
 
 bool GLImageOzoneNativePixmap::Initialize(ui::NativePixmap* pixmap,
                                           GpuMemoryBuffer::Format format) {
   DCHECK(!pixmap_);
 
   bool result = true;
   if (pixmap->GetEGLClientBuffer()) {
     EGLint attrs[] = {EGL_IMAGE_PRESERVED_KHR, EGL_TRUE, EGL_NONE};
     result = GLImageEGL::Initialize(EGL_NATIVE_PIXMAP_KHR,
@@ skipping 32 matching lines @@
     pixmap_ = pixmap;
   return result;
 }
 
 unsigned GLImageOzoneNativePixmap::GetInternalFormat() {
   return internalformat_;
 }
 
 void GLImageOzoneNativePixmap::Destroy(bool have_context) {
   GLImageEGL::Destroy(have_context);
-  pixmap_ = nullptr;
 }
 
 bool GLImageOzoneNativePixmap::ScheduleOverlayPlane(AcceleratedWidget widget,
                                                     int z_order,
                                                     OverlayTransform transform,
                                                     const Rect& bounds_rect,
                                                     const RectF& crop_rect) {
   DCHECK(pixmap_);
   return pixmap_->ScheduleOverlayPlane(widget, z_order, transform, bounds_rect,
                                        crop_rect);
 }
 
 }  // namespace gfx