ozone: Implement support for CreateGpuMemoryBufferFromHandle for OzoneNativePixmap backed GMBs.

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

Index: ui/ozone/platform/drm/gpu/gbm_buffer.cc
diff --git a/ui/ozone/platform/drm/gpu/gbm_buffer.cc b/ui/ozone/platform/drm/gpu/gbm_buffer.cc
index 045caadf2a77ec75378ea7d3e151027b2b85172a..5023d3004e834e1a08971b25aafff3c2567fdd26 100644
--- a/ui/ozone/platform/drm/gpu/gbm_buffer.cc
+++ b/ui/ozone/platform/drm/gpu/gbm_buffer.cc
@@ -73,19 +73,25 @@ scoped_refptr<GbmBuffer> GbmBuffer::CreateBuffer(
   return buffer;
 }
 
-GbmPixmap::GbmPixmap(const scoped_refptr<GbmBuffer>& buffer,
-                     GbmSurfaceFactory* surface_manager)
-    : buffer_(buffer), surface_manager_(surface_manager) {}
+GbmPixmap::GbmPixmap(GbmSurfaceFactory* surface_manager)
+    : surface_manager_(surface_manager) {}
 
-bool GbmPixmap::Initialize() {
+void GbmPixmap::Initialize(int dma_buf, int dma_buf_pitch) {
+  dma_buf_ = dma_buf;
+  dma_buf_pitch_ = dma_buf_pitch;
+}
+
+bool GbmPixmap::InitializeFromBuffer(const scoped_refptr<GbmBuffer>& buffer) {
   // We want to use the GBM API because it's going to call into libdrm
   // which might do some optimizations on buffer allocation,
   // especially when sharing buffers via DMABUF.
-  dma_buf_ = gbm_bo_get_fd(buffer_->bo());
-  if (dma_buf_ < 0) {
+  int dma_buf = gbm_bo_get_fd(buffer->bo());
+  if (dma_buf < 0) {
     PLOG(ERROR) << "Failed to export buffer to dma_buf";
     return false;
   }
+  Initialize(dma_buf, gbm_bo_get_stride(buffer->bo()));
+  buffer_ = buffer;
   return true;
 }
 
@@ -107,7 +113,7 @@ gfx::NativePixmapHandle GbmPixmap::ExportHandle() {
   }
 
   handle.fd = base::FileDescriptor(dmabuf_fd, true /* auto_close */);
-  handle.stride = gbm_bo_get_stride(buffer_->bo());
+  handle.stride = dma_buf_pitch_;
   return handle;
 }
 
@@ -125,7 +131,7 @@ int GbmPixmap::GetDmaBufFd() {
 }
 
 int GbmPixmap::GetDmaBufPitch() {
-  return gbm_bo_get_stride(buffer_->bo());
+  return dma_buf_pitch_;
 }
 
 bool GbmPixmap::ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
@@ -133,7 +139,6 @@ bool GbmPixmap::ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
                                      gfx::OverlayTransform plane_transform,
                                      const gfx::Rect& display_bounds,
                                      const gfx::RectF& crop_rect) {
-  DCHECK(buffer_->GetUsage() == gfx::BufferUsage::SCANOUT);
   gfx::Size required_size;
   if (plane_z_order &&
       ShouldApplyScaling(display_bounds, crop_rect, &required_size)) {
@@ -146,6 +151,12 @@ bool GbmPixmap::ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
     }
   }
 
+  if (!buffer_) {

[piman, 2015/10/08 23:24:36]

I assume eventually we'll want to support this for imported handles too, right?
Do we have an idea what we need to do to make it possible?

[reveman, 2015/10/09 12:47:02]

I haven't looked at this much in detail but it seems like we need to implement
gbm_bo_import(GBM_BO_IMPORT_FD) in minigbm for this to work properly. Created a
bug and linked to it here in a TODO.

+    PLOG(ERROR) << "ScheduleOverlayPlane requires a buffer.";
+    return false;
+  }
+
+  DCHECK(buffer_->GetUsage() == gfx::BufferUsage::SCANOUT);
   surface_manager_->GetSurface(widget)->QueueOverlayPlane(OverlayPlane(
       buffer_, plane_z_order, plane_transform, display_bounds, crop_rect));
   return true;
@@ -159,6 +170,11 @@ bool GbmPixmap::ShouldApplyScaling(const gfx::Rect& display_bounds,
     return false;
   }
 
+  if (!buffer_) {
+    PLOG(ERROR) << "ShouldApplyScaling requires a buffer.";
+    return false;
+  }
+
   gfx::Size pixmap_size = buffer_->GetSize();
   // If the required size is not integer-sized, round it to the next integer.
   *required_size = gfx::ToCeiledSize(