Implement DRM Native Pixmap using prime buffer

ui/ozone/platform/drm/client_native_pixmap_factory_gbm.cc

Index: ui/ozone/platform/drm/client_native_pixmap_factory_gbm.cc
diff --git a/ui/ozone/platform/drm/client_native_pixmap_factory_gbm.cc b/ui/ozone/platform/drm/client_native_pixmap_factory_gbm.cc
index 27bb4a4ca1a62d43bb4dad8c9ca7936fb7184f07..5c67da6d305586d971fcc938690586d64bc142b0 100644
--- a/ui/ozone/platform/drm/client_native_pixmap_factory_gbm.cc
+++ b/ui/ozone/platform/drm/client_native_pixmap_factory_gbm.cc
@@ -6,9 +6,12 @@
 
 #include <utility>
 
+#include "base/command_line.h"
 #include "base/macros.h"
 #include "ui/gfx/native_pixmap_handle_ozone.h"
+#include "ui/ozone/platform/drm/common/client_native_pixmap_dmabuf.h"
 #include "ui/ozone/public/client_native_pixmap_factory.h"  // nogncheck
+#include "ui/ozone/public/ozone_switches.h"
 
 #if defined(USE_VGEM_MAP)
 #include "ui/ozone/platform/drm/common/client_native_pixmap_vgem.h"
@@ -58,6 +61,9 @@ class ClientNativePixmapFactoryGbm : public ClientNativePixmapFactory {
                format == gfx::BufferFormat::BGRX_8888;
       case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE:
       case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE_PERSISTENT: {
+        if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+                switches::kOzoneUseDmaBufMmap))

[spang, 2016/03/21 23:24:20]

Check the command line in the constructor or Initialize().

[vignatti (out of this project), 2016/03/22 20:24:29]

I was actually thinking about removing the cmd line option altogether with the
vgem support now. 

+          return format == gfx::BufferFormat::BGRA_8888;
 #if defined(USE_VGEM_MAP)
         return vgem_fd_.is_valid() && format == gfx::BufferFormat::BGRA_8888;
 #else
@@ -77,6 +83,10 @@ class ClientNativePixmapFactoryGbm : public ClientNativePixmapFactory {
     switch (usage) {
       case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE:
       case gfx::BufferUsage::GPU_READ_CPU_READ_WRITE_PERSISTENT:
+        if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+                switches::kOzoneUseDmaBufMmap))
+          return ClientNativePixmapDmaBuf::ImportFromDmabuf(
+              scoped_fd.get(), size, handle.stride);
 #if defined(USE_VGEM_MAP)
         // A valid |vgem_fd_| is required to acquire a VGEM bo. |vgem_fd_| is
         // set before a widget is created.