commit 8776b325f2b740c7061b34ea9a813102aeccc9ce
author Colin Blundell <blundell@chromium.org> Mon Dec 18 12:57:18 2023
committer Chromium LUCI CQ <chromium-scoped@luci-project-accounts.iam.gserviceaccount.com> Mon Dec 18 12:57:18 2023
tree 60dc2c6367195865717f4911797fc6a7a61c6906
parent cb8cccc2bda72585b5d6a2946789d0dc80ad02c4

[Blink] Convert DrawingBuffer to MappableSharedImage

This CL converts DrawingBuffer from using GpuMemoryBuffer to using
MappableSharedImage. The conversion is straightforward:

* Currently DrawingBuffer creates a GMB and then immediately creates
  an SI from the GMB's handle.
* We instead create an SI via the CreateSI() path that causes a backing
  GMBHandle to be created internally.
* Where the code previously checked for the GMB having been created, we
  now track a bool explicitly for whether the MapppableSI was created.
* We remove ColorBuffer's keeping the GMB alive for its lifetime.
  ColorBuffer already keeps the SI alive for its lifetime (it's put into
  `back_buffer_mailbox`, which is passed to the created ColorBuffer and
  on which that ColorBuffer calls DestroySI() at the same time as it
  resets() the gmb)
* We remove the check for Platform having a GMBManager from
  ShouldUseChromiumImage(). This check only served to ensure that the
  code didn't try to create a GMB from a null GMBManager. MappableSI
  doesn't use Platform's GMBManager to create GMBs internally. In the
  current structure of the code any failure to create MappableSI will
  flow down to the non-ShouldUseChromiumImage() case, as the code is
  currently doing if there is no GMBManager.

Bug: 1431497
Change-Id: If15f199ee6d63176e70625c99b567c84fffcf125
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5119550
Commit-Queue: Colin Blundell <blundell@chromium.org>
Reviewed-by: Vasiliy Telezhnikov <vasilyt@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1238562}