ozone: Add overlay candidate implementation that queries support via IPC

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

Index: ui/ozone/platform/drm/host/drm_host_overlay_candidates.cc
diff --git a/ui/ozone/platform/drm/host/drm_host_overlay_candidates.cc b/ui/ozone/platform/drm/host/drm_host_overlay_candidates.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a54bdf95deaa83393751eac60e073fa5292108e2
--- /dev/null
+++ b/ui/ozone/platform/drm/host/drm_host_overlay_candidates.cc
@@ -0,0 +1,127 @@
+#include "ui/ozone/platform/drm/host/drm_host_overlay_candidates.h"
+
+#include <algorithm>
+
+#include "ui/gfx/geometry/rect_conversions.h"
+#include "ui/ozone/common/gpu/ozone_gpu_messages.h"
+#include "ui/ozone/platform/drm/host/drm_gpu_platform_support_host.h"
+
+namespace ui {
+
+namespace {
+const size_t kMaxCacheSize = 10000;
+}  // namespace
+
+bool DrmHostOverlayCandidates::OverlayCompare::operator()(
+    const OverlayCheck_Params& l,
+    const OverlayCheck_Params& r) {
+  return l.plane_z_order < r.plane_z_order ||
+         (l.plane_z_order == r.plane_z_order &&
+          (l.display_rect < r.display_rect ||
+           (l.display_rect == r.display_rect &&
+            (l.format < r.format ||
+             (l.format == r.format &&
+              (l.transform < r.transform ||
+               (l.transform == r.transform &&
+                (l.buffer_size.width() < r.buffer_size.width() ||
+                 (l.buffer_size.width() == r.buffer_size.width() &&
+                  l.buffer_size.height() < r.buffer_size.height())))))))));
+}
+
+DrmHostOverlayCandidates::DrmHostOverlayCandidates(
+    gfx::AcceleratedWidget widget,
+    DrmGpuPlatformSupportHost* platform_support)
+    : widget_(widget), platform_support_(platform_support) {
+  platform_support_->RegisterHandler(this);
+}
+
+DrmHostOverlayCandidates::~DrmHostOverlayCandidates() {
+  platform_support_->UnregisterHandler(this);
+}
+
+void DrmHostOverlayCandidates::CheckOverlaySupport(
+    OverlaySurfaceCandidateList* candidates) {
+  if (candidates->size() == 2)
+    CheckSingleOverlay(candidates);
+}
+
+void DrmHostOverlayCandidates::CheckSingleOverlay(
+    OverlaySurfaceCandidateList* candidates) {
+  OverlayCandidatesOzone::OverlaySurfaceCandidate* first = &(*candidates)[0];
+  OverlayCandidatesOzone::OverlaySurfaceCandidate* second = &(*candidates)[1];
+  OverlayCandidatesOzone::OverlaySurfaceCandidate* overlay;
+  if (first->plane_z_order == 0) {
+    overlay = second;
+  } else if (second->plane_z_order == 0) {
+    overlay = first;
+  } else {
+    return;
+  }
+  // 0.01 constant chosen to match DCHECKs in gfx::ToNearestRect and avoid
+  // that code asserting on quads that we accept.
+  if (!gfx::IsNearestRectWithinDistance(overlay->display_rect, 0.01f))
+    return;
+  if (overlay->transform == gfx::OVERLAY_TRANSFORM_INVALID)
+    return;
+
+  OverlayCheck_Params lookup(*overlay);
+  auto iter = cache_.find(lookup);
+  if (iter == cache_.end()) {
+    if (cache_.size() > kMaxCacheSize)
+      cache_.clear();
+    cache_[lookup] = false;
+    SendRequest(*candidates, lookup);
+  } else {
+    overlay->overlay_handled = iter->second;
+  }
+}
+
+void DrmHostOverlayCandidates::OnChannelEstablished(
+    int host_id,
+    scoped_refptr<base::SingleThreadTaskRunner> send_runner,
+    const base::Callback<void(IPC::Message*)>& sender) {
+}
+
+void DrmHostOverlayCandidates::OnChannelDestroyed(int host_id) {
+}
+
+bool DrmHostOverlayCandidates::OnMessageReceived(const IPC::Message& message) {
+  bool handled = false;
+  IPC_BEGIN_MESSAGE_MAP_WITH_PARAM(DrmHostOverlayCandidates, message, &handled)
+  IPC_MESSAGE_FORWARD(OzoneHostMsg_OverlayCapabilitiesReceived, this,
+                      DrmHostOverlayCandidates::OnOverlayResult)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+void DrmHostOverlayCandidates::SendRequest(
+    const OverlaySurfaceCandidateList& candidates,
+    const OverlayCheck_Params& check) {
+  if (!platform_support_->IsConnected())
+    return;
+  pending_checks_.push_back(check);
+  std::vector<OverlayCheck_Params> list;
+  for (const auto& candidate : candidates)
+    list.push_back(OverlayCheck_Params(candidate));
+  platform_support_->Send(
+      new OzoneGpuMsg_CheckOverlayCapabilities(widget_, list));
+}
+
+void DrmHostOverlayCandidates::OnOverlayResult(bool* handled,
+                                               gfx::AcceleratedWidget widget,
+                                               bool result) {
+  if (widget != widget_)
+    return;
+  *handled = true;
+  DCHECK(!pending_checks_.empty());
+  ProcessResult(pending_checks_.front(), result);
+  pending_checks_.pop_front();
+}
+
+void DrmHostOverlayCandidates::ProcessResult(const OverlayCheck_Params& check,
+                                             bool result) {
+  if (result)
+    cache_[check] = true;
+}
+
+}  // namespace ui