ozone: Add overlay candidate implementation that queries support via IPC

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

Index: ui/ozone/platform/drm/gpu/drm_gpu_platform_support.cc
diff --git a/ui/ozone/platform/drm/gpu/drm_gpu_platform_support.cc b/ui/ozone/platform/drm/gpu/drm_gpu_platform_support.cc
index e546bf2ed03c931898df1a4385ba2352788a56b9..2cd3d58c71287e573c58ac75e500faca65b9d0d2 100644
--- a/ui/ozone/platform/drm/gpu/drm_gpu_platform_support.cc
+++ b/ui/ozone/platform/drm/gpu/drm_gpu_platform_support.cc
@@ -13,6 +13,7 @@
 #include "ui/ozone/platform/drm/gpu/drm_device_manager.h"
 #include "ui/ozone/platform/drm/gpu/drm_gpu_display_manager.h"
 #include "ui/ozone/platform/drm/gpu/drm_window.h"
+#include "ui/ozone/platform/drm/gpu/scanout_buffer.h"
 #include "ui/ozone/platform/drm/gpu/screen_manager.h"
 
 namespace ui {
@@ -167,10 +168,12 @@ class DrmGpuPlatformSupportMessageFilter : public IPC::MessageFilter {
 DrmGpuPlatformSupport::DrmGpuPlatformSupport(
     DrmDeviceManager* drm_device_manager,
     ScreenManager* screen_manager,
+    ScanoutBufferGenerator* buffer_generator,
     scoped_ptr<DrmGpuDisplayManager> display_manager)
     : sender_(NULL),
       drm_device_manager_(drm_device_manager),
       screen_manager_(screen_manager),
+      buffer_generator_(buffer_generator),
       display_manager_(display_manager.Pass()) {
   filter_ = new DrmGpuPlatformSupportMessageFilter(
       screen_manager, base::Bind(&DrmGpuPlatformSupport::SetIOTaskRunner,
@@ -217,6 +220,8 @@ bool DrmGpuPlatformSupport::OnMessageReceived(const IPC::Message& message) {
   IPC_MESSAGE_HANDLER(OzoneGpuMsg_GetHDCPState, OnGetHDCPState)
   IPC_MESSAGE_HANDLER(OzoneGpuMsg_SetHDCPState, OnSetHDCPState)
   IPC_MESSAGE_HANDLER(OzoneGpuMsg_SetGammaRamp, OnSetGammaRamp);
+  IPC_MESSAGE_HANDLER(OzoneGpuMsg_CheckOverlayCapabilities,
+                      OnCheckOverlayCapabilities)
   IPC_MESSAGE_UNHANDLED(handled = false);
   IPC_END_MESSAGE_MAP()
 
@@ -260,6 +265,47 @@ void DrmGpuPlatformSupport::OnCursorMove(gfx::AcceleratedWidget widget,
   screen_manager_->GetWindow(widget)->MoveCursor(location);
 }
 
+void DrmGpuPlatformSupport::OnCheckOverlayCapabilities(
+    gfx::AcceleratedWidget widget,
+    uint32_t request_id,
+    const std::vector<OverlayCheck_Params>& overlays) {
+  sender_->Send(new OzoneHostMsg_OverlayCapabilitiesReceived(
+      widget, request_id,
+      TestOverlayCapabilities(screen_manager_->GetWindow(widget), overlays)));
+}
+
+bool DrmGpuPlatformSupport::TestOverlayCapabilities(
+    DrmWindow* window,
+    const std::vector<OverlayCheck_Params>& overlays) {
+  HardwareDisplayController* hdc = window->GetController();
+  if (!hdc)
+    return false;
+  scoped_refptr<DrmDevice> drm = hdc->GetAllocationDrmDevice();
+
+  OverlayPlaneList planes;
+  for (const auto& overlay : overlays) {
+    scoped_refptr<ScanoutBuffer> buffer;
+    if (overlay.plane_z_order == 0) {
+      buffer = buffer_generator_->Create(drm, window->bounds().size());
+    } else {
+      // It is possible that the cc rect we get actually falls off the edge of
+      // the screen. Usually this is prevented via things like status bars
+      // blocking overlaying or cc clipping it, but in case it wasn't properly
+      // clipped (since GL will render this situation fine) just ignore it here.
+      // This should be an extremely rare occurrance.
+      if (!window->bounds().Contains(overlay.display_rect))
+        return false;
+      buffer = buffer_generator_->Create(drm, overlay.buffer_size);
+    }
+    if (!buffer)
+      return false;
+    planes.push_back(OverlayPlane(buffer, overlay.plane_z_order,
+                                  overlay.transform, overlay.display_rect,
+                                  gfx::RectF(gfx::Size(1, 1))));
+  }
+  return window->TestPageFlip(planes);
+}
+
 void DrmGpuPlatformSupport::OnRefreshNativeDisplays() {
   sender_->Send(
       new OzoneHostMsg_UpdateNativeDisplays(display_manager_->GetDisplays()));