ozone: Allocate scanout buffer according to KMS modifiers

ui/ozone/platform/drm/gpu/hardware_display_controller.h

Index: ui/ozone/platform/drm/gpu/hardware_display_controller.h
diff --git a/ui/ozone/platform/drm/gpu/hardware_display_controller.h b/ui/ozone/platform/drm/gpu/hardware_display_controller.h
index 3738cf27d4459d4026e10f755c1b3ccc31d4cf6a..00b07a1f54bbcad7b317fe3b2a7ff6226bde0733 100644
--- a/ui/ozone/platform/drm/gpu/hardware_display_controller.h
+++ b/ui/ozone/platform/drm/gpu/hardware_display_controller.h
@@ -127,6 +127,11 @@ class HardwareDisplayController {
 
   bool IsFormatSupported(uint32_t fourcc_format, uint32_t z_order) const;
 
+  // Add GBM usage flags to |flags| as needed for the |format| and

[Daniele Castagna, 2016/12/20 18:03:28]

Does this comment need to be updated with the new GetFormatModifiers definition?

[hoegsberg1, 2016/12/22 23:05:21]

Acknowledged.

+  // |flags| passed in. This lets a controller set additional flags to
+  // make sure the allocated buffer can be scanned out.
+  std::vector<uint64_t> GetFormatModifiers(uint32_t format);
+
   // Set the hardware cursor to show the contents of |surface|.
   bool SetCursor(const scoped_refptr<ScanoutBuffer>& buffer);