display_compositor: Move CompositorOverlayCandidateValidator from content.

components/display_compositor/BUILD.gn

Index: components/display_compositor/BUILD.gn
diff --git a/components/display_compositor/BUILD.gn b/components/display_compositor/BUILD.gn
index d9964b7ce5379f8cfc87b7722e114da946bd7005..00c47ff2aacfb0aa86daec5192a3b2ae2de0780d 100644
--- a/components/display_compositor/BUILD.gn
+++ b/components/display_compositor/BUILD.gn
@@ -2,12 +2,14 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/config/ui.gni")
 import("//testing/test.gni")
 
 component("display_compositor") {
   sources = [
     "buffer_queue.cc",
     "buffer_queue.h",
+    "compositor_overlay_candidate_validator.h",
     "display_compositor_export.h",
     "gl_helper.cc",
     "gl_helper.h",
@@ -30,6 +32,29 @@ component("display_compositor") {
     "//skia",
     "//ui/gfx",
   ]
+
+  if (is_mac) {
+    sources += [
+      "compositor_overlay_candidate_validator_mac.h",
+      "compositor_overlay_candidate_validator_mac.mm",
+    ]
+  }
+
+  if (is_android) {
+    sources += [
+      "compositor_overlay_candidate_validator_android.cc",
+      "compositor_overlay_candidate_validator_android.h",
+    ]
+  }
+
+  if (use_ozone) {
+    sources += [
+      "compositor_overlay_candidate_validator_ozone.cc",
+      "compositor_overlay_candidate_validator_ozone.h",
+    ]
+
+    deps += [ "//ui/ozone" ]
+  }
 }
 
 test("display_compositor_unittests") {