gpu: support R16 GPUMemoryBuffer

ui/ozone/platform/drm/common/drm_util.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/common/drm_util.h"
 
 #include <drm_fourcc.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <sys/mman.h>
 #include <xf86drm.h>
 #include <xf86drmMode.h>
 #include <algorithm>
 #include <utility>
 
 #include "base/containers/flat_map.h"
 #include "base/memory/ptr_util.h"
 #include "ui/display/util/edid_parser.h"
 
+#if !defined(DRM_FORMAT_R16)
+// TODO(riju): after libdrm has this definition, remove it.
+#define DRM_FORMAT_R16 fourcc_code('R', '1', '6', ' ')

[reveman, 2017/06/14 17:47:22]

upstream seems to have this. can we instead just update libdrm in third_party
and on chromeos before we land this?

[riju_, 2017/06/20 13:21:31]

Created bug: https://bugs.chromium.org/p/chromium/issues/detail?id=733703

ChromiumOS CLs:
(libdrm: upgrade): https://chromium-review.googlesource.com/c/539275/
(libpciaccess: upgrade): https://chromium-review.googlesource.com/c/539031/

Not familiar with chromeos package upgrades, so upgraded in wrong overlay.
What I understood from Stéphane Marchesin in 
https://chromium-review.googlesource.com/c/539275/#message-a3485b4a0f5d5d5152...
is that, updating libdrm is already in their plans.
There is already libdrm 2.4.75 in a branch, where some patches have to
rebased/applied and then it would be moved to master.
https://chromium.googlesource.com/chromiumos/third_party/libdrm/+/chromeos-2....,

 
Next Step:
So I suggest we check-in this CL, and I will update DEPS (and fix this TODO)
when libdrm is updated.
This approach was taken in https://codereview.chromium.org/2758013002

+#endif
+
 namespace ui {
 
 namespace {
 
 static const size_t kDefaultCursorWidth = 64;
 static const size_t kDefaultCursorHeight = 64;
 
 bool IsCrtcInUse(
     uint32_t crtc,
     const std::vector<std::unique_ptr<HardwareDisplayControllerInfo>>&
@@ skipping 326 matching lines @@
     params.native_mode = params.modes.front();
   }
 
   return params;
 }
 
 int GetFourCCFormatFromBufferFormat(gfx::BufferFormat format) {
   switch (format) {
     case gfx::BufferFormat::R_8:
       return DRM_FORMAT_R8;
+    case gfx::BufferFormat::R_16:
+      return DRM_FORMAT_R16;
     case gfx::BufferFormat::RG_88:
       return DRM_FORMAT_GR88;
     case gfx::BufferFormat::RGBA_8888:
       return DRM_FORMAT_ABGR8888;
     case gfx::BufferFormat::RGBX_8888:
       return DRM_FORMAT_XBGR8888;
     case gfx::BufferFormat::BGRA_8888:
       return DRM_FORMAT_ARGB8888;
     case gfx::BufferFormat::BGRX_8888:
       return DRM_FORMAT_XRGB8888;
@@ skipping 57 matching lines @@
     case gfx::BufferFormat::YUV_420_BIPLANAR:
       return DRM_FORMAT_NV12;
     case gfx::BufferFormat::YVU_420:
       return DRM_FORMAT_YVU420;
     default:
       NOTREACHED();
       return 0;
   }
 }
 }  // namespace ui