Revert incorrect plane in_use check

Revert to previous version (pre crrev.com/c/2039752).

|plane| is shared state between previously submitted frame and the current frame. We can't rely on that state since generating the new frame would have updated the plane state. It's existence in the |old_plane_list| is sufficient to signal that |plane| was previously used.

BUG=1045743,1053603,1053839
TEST=ozone_unittests

Change-Id: I08cdb1ae7962debf7ec35eea6f00291995454d34
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2062684Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Commit-Queue: Mark Yacoub <markyacoub@google.com>
Auto-Submit: Mark Yacoub <markyacoub@google.com>
Cr-Commit-Position: refs/heads/master@{#743188}

ui/ozone/platform/drm/gpu/hardware_display_plane_manager_atomic.cc

@@ -127,16 +127,20 @@ bool HardwareDisplayPlaneManagerAtomic::Commit(
 
   for (HardwareDisplayPlane* plane : plane_list->old_plane_list) {
     if (!base::Contains(plane_list->plane_list, plane)) {
-      if (plane->in_use()) {
-        // This plane is being released, so we need to zero it.
-        plane->set_in_use(false);
-        HardwareDisplayPlaneAtomic* atomic_plane =
-            static_cast<HardwareDisplayPlaneAtomic*>(plane);
-        atomic_plane->SetPlaneData(plane_list->atomic_property_set.get(), 0, 0,
-                                   gfx::Rect(), gfx::Rect(),
-                                   gfx::OVERLAY_TRANSFORM_NONE,
-                                   base::kInvalidPlatformFile);
-      }
+      // |plane| is shared state between |old_plane_list| and |plane_list|.
+      // When we call BeginFrame(), we reset in_use since we need to be able to
+      // allocate the planes as needed. The current frame might not need to use
+      // |plane|, thus |plane->in_use()| would be false even though the previous
+      // frame used it. It's existence in |old_plane_list| is sufficient to
+      // signal that |plane| was in use previously.
+      // TODO(markyacoub): Add a unittest that planes should be reset whether
+      // they're originally in_use or not.
+      plane->set_in_use(false);
+      HardwareDisplayPlaneAtomic* atomic_plane =
+          static_cast<HardwareDisplayPlaneAtomic*>(plane);
+      atomic_plane->SetPlaneData(
+          plane_list->atomic_property_set.get(), 0, 0, gfx::Rect(), gfx::Rect(),
+          gfx::OVERLAY_TRANSFORM_NONE, base::kInvalidPlatformFile);
     }
   }