[TaskScheduler]: Migrate off of AssertBlockingAllowedDeprecated in /ui/ozone/platform/drm

base::AssertBlockingAllowedDeprecated is deprecated in favor of
ScopedBlockingCall, which serves as a precise annotation of
the scope that may/will block.

Please make sure of the following:
  - ScopedBlockingCall is instantiated in a scope with minimal CPU usage.
    If this is not the case, ScopedBlockingCall should be instantiated
    closer to the blocking call. See scoped_blocking_call.h for more
    info. Please let me know when/where the blocking call happens if this needs
    to be changed.
  - Parameter |blocking_type| matches expectation:
      MAY_BLOCK: The call might block (e.g. file I/O that might hit in memory cache).
      WILL_BLOCK: The call will definitely block (e.g. cache already checked and now pinging
        server synchronously).
    See BlockingType for more info. While I assumed MAY_BLOCK by default, that might
    not be the best fit if we know that this callsite is guaranteed to block.
  - The ScopedBlockingCall's scope covers the entirety of the blocking operation
    previously asserted against by the AssertBlockingAllowed().
  - Calls to blocking //base APIs don't need to be annotated
    with ScopedBlockingCall. All blocking //base APIs (e.g. base::ReadFileToString, base::File::Read,
    base::SysInfo::AmountOfFreeDiskSpace, base::WaitableEvent::Wait, etc.) have their
    own internal annotations.

Refer to the top-level CL if necessary :
https://chromium-review.googlesource.com/c/chromium/src/+/1338391

Please CQ if LGTY!

This CL was uploaded by git cl split.

R=dnicoara@chromium.org

Bug: 903957
Change-Id: Ie052b76a8c8c4083857f9deb5d46eb03e1cb15e6
Reviewed-on: https://chromium-review.googlesource.com/c/1338482
Commit-Queue: Etienne Pierre-Doray <etiennep@chromium.org>
Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613139}

ui/ozone/platform/drm/host/drm_device_handle.cc

@@ -11,7 +11,7 @@
 
 #include "base/files/file_path.h"
 #include "base/posix/eintr_wrapper.h"
-#include "base/threading/thread_restrictions.h"
+#include "base/threading/scoped_blocking_call.h"
 #include "base/time/time.h"
 
 namespace ui {
@@ -38,8 +38,11 @@ DrmDeviceHandle::DrmDeviceHandle() {
 }
 
 DrmDeviceHandle::~DrmDeviceHandle() {
-  if (file_.is_valid())
-    base::AssertBlockingAllowedDeprecated();
+  if (file_.is_valid()) {
+    base::ScopedBlockingCall scoped_blocking_call(
+        base::BlockingType::MAY_BLOCK);
+    file_.reset();
+  }
 }
 
 bool DrmDeviceHandle::Initialize(const base::FilePath& dev_path,
@@ -48,7 +51,7 @@ bool DrmDeviceHandle::Initialize(const base::FilePath& dev_path,
   // expected path, so use a CHECK instead of a DCHECK. The sys_path is only
   // used a label and is otherwise unvalidated.
   CHECK(dev_path.DirName() == base::FilePath("/dev/dri"));
-  base::AssertBlockingAllowedDeprecated();
+  base::ScopedBlockingCall scoped_blocking_call(base::BlockingType::MAY_BLOCK);
 
   int num_auth_attempts = 0;
   bool logged_warning = false;