ozone: Don't assume AddFB succeeds when importing buffers.

ui/ozone/platform/drm/gpu/gbm_buffer.cc

 // Copyright 2014 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/ozone/platform/drm/gpu/gbm_buffer.h"
 
 #include <drm.h>
 #include <fcntl.h>
 #include <gbm.h>
 #include <xf86drm.h>
@@ skipping 165 matching lines @@
     const scoped_refptr<GbmDevice>& gbm,
     uint32_t format,
     const gfx::Size& size,
     std::vector<base::ScopedFD>&& fds,
     const std::vector<gfx::NativePixmapPlane>& planes) {
   TRACE_EVENT2("drm", "GbmBuffer::CreateBufferFromFD", "device",
                gbm->device_path().value(), "size", size.ToString());
   DCHECK_LE(fds.size(), planes.size());
   DCHECK_EQ(planes[0].offset, 0);
 
-  // Use scanout if supported.
-  bool use_scanout =
+  // Try to use scanout if supported.
+  bool try_scanout =
       gbm_device_is_format_supported(
           gbm->device(), format, GBM_BO_USE_SCANOUT | GBM_BO_USE_RENDERING) &&
       (planes.size() == 1);
 
   gbm_bo* bo = nullptr;
-  if (use_scanout) {
+  if (try_scanout) {
     struct gbm_import_fd_data fd_data;
     fd_data.fd = fds[0].get();
     fd_data.width = size.width();
     fd_data.height = size.height();
     fd_data.stride = planes[0].stride;
     fd_data.format = format;
 
     // The fd passed to gbm_bo_import is not ref-counted and need to be
     // kept open for the lifetime of the buffer.
     bo = gbm_bo_import(gbm->device(), GBM_BO_IMPORT_FD, &fd_data,
                        GBM_BO_USE_SCANOUT | GBM_BO_USE_RENDERING);
     if (!bo) {
       LOG(ERROR) << "nullptr returned from gbm_bo_import";
       return nullptr;
     }
   }
 
   uint32_t flags = GBM_BO_USE_RENDERING;
-  if (use_scanout)
+  if (try_scanout)
     flags |= GBM_BO_USE_SCANOUT;
   scoped_refptr<GbmBuffer> buffer(new GbmBuffer(
       gbm, bo, format, flags, 0, 0, std::move(fds), size, std::move(planes)));
-  // If scanout support for buffer is expected then make sure we managed to
-  // create a framebuffer for it as otherwise using it for scanout will fail.
-  if (use_scanout && !buffer->GetFramebufferId())
-    return nullptr;
 
   return buffer;
 }
 
 GbmPixmap::GbmPixmap(GbmSurfaceFactory* surface_manager,
                      const scoped_refptr<GbmBuffer>& buffer)
     : surface_manager_(surface_manager), buffer_(buffer) {}
 
 void GbmPixmap::SetProcessingCallback(
     const ProcessingCallback& processing_callback) {
@@ skipping 104 matching lines @@
   DCHECK(!processing_callback_.is_null());
   if (!processing_callback_.Run(this, processed_pixmap_)) {
     LOG(ERROR) << "Failed processing NativePixmap";
     return nullptr;
   }
 
   return processed_pixmap_->buffer();
 }
 
 }  // namespace ui