[ozone/wayland] Add possibility to create wl buffer immediately.

zwp_linux_dmabuf protocol is able to create the wl_buffer both
synchronously and asynchronously. This feature depends on the
protocol version.

Thus, if the protocol corresponds to the version, when the buffer
can be created immediately, utilize it and do not wait for the
answer from the Wayland compositor.

Bug: 939794
Change-Id: I14fcad5eae8bcce3b24b662867c13948eb7e4ae6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1572344
Commit-Queue: Maksim Sisov <msisov@igalia.com>
Reviewed-by: Michael Spang <spang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654800}

ui/ozone/platform/wayland/host/wayland_zwp_linux_dmabuf.cc

@@ -12,6 +12,10 @@
 
 namespace ui {
 
+namespace {
+constexpr uint32_t kImmedVerstion = 3;
+}
+
 WaylandZwpLinuxDmabuf::WaylandZwpLinuxDmabuf(
     zwp_linux_dmabuf_v1* zwp_linux_dmabuf,
     WaylandConnection* connection)
@@ -45,10 +49,6 @@ void WaylandZwpLinuxDmabuf::CreateBuffer(base::File file,
   struct zwp_linux_buffer_params_v1* params =
       zwp_linux_dmabuf_v1_create_params(zwp_linux_dmabuf_.get());
 
-  // Store the |params| with the corresponding |callback| to identify newly
-  // created buffer and notify the client about it via the |callback|.
-  pending_params_.insert(std::make_pair(params, std::move(callback)));
-
   base::ScopedFD fd(file.TakePlatformFile());
 
   for (size_t i = 0; i < planes_count; i++) {
@@ -65,10 +65,23 @@ void WaylandZwpLinuxDmabuf::CreateBuffer(base::File file,
                                    offsets[i], strides[i], modifier_hi,
                                    modifier_lo);
   }
-  zwp_linux_buffer_params_v1_add_listener(params, &params_listener, this);
-  zwp_linux_buffer_params_v1_create(params, size.width(), size.height(), format,
-                                    0);
 
+  // It's possible to avoid waiting until the buffer is created and have it
+  // immediately. This method is only available since the protocol version 3.
+  if (zwp_linux_dmabuf_v1_get_version(zwp_linux_dmabuf_.get()) >=
+      kImmedVerstion) {
+    wl::Object<wl_buffer> buffer(zwp_linux_buffer_params_v1_create_immed(
+        params, size.width(), size.height(), format, 0));
+    std::move(callback).Run(std::move(buffer));
+  } else {
+    // Store the |params| with the corresponding |callback| to identify newly
+    // created buffer and notify the client about it via the |callback|.
+    pending_params_.insert(std::make_pair(params, std::move(callback)));
+
+    zwp_linux_buffer_params_v1_add_listener(params, &params_listener, this);
+    zwp_linux_buffer_params_v1_create(params, size.width(), size.height(),
+                                      format, 0);
+  }
   connection_->ScheduleFlush();
 }