Check ENABLE_MEDIA_OVERLAY before creating media_overlay_

Only create media_overlay_ if ENABLE_MEDIA_OVERLAY is defined

Bug: b/156276792
Test: Build cast_shell
Change-Id: I490ab1ff2fe45ef516fa108b8e30389abb052fc2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2212969
Commit-Queue: Shawn Gallea <sagallea@google.com>
Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Reviewed-by: Sean Topping <seantopping@chromium.org>
Cr-Commit-Position: refs/heads/master@{#771271}

chromecast/chromecast.gni

@@ -131,6 +131,9 @@ declare_args() {
 
   # Extra rpath to use for standalone services.
   iot_service_rpath = ""
+
+  # Set to true to enable media overlay for volume bar, etc.
+  enable_media_overlay = false
 }
 
 declare_args() {

chromecast/ui/BUILD.gn

@@ -57,6 +57,10 @@ cast_source_set("aura_components") {
   } else {
     sources += [ "aura_components_dummy.cc" ]
   }
+
+  if (enable_media_overlay) {
+    defines = [ "ENABLE_MEDIA_OVERLAY" ]
+  }
 }
 
 if (use_aura) {

chromecast/ui/aura_components.cc

@@ -9,7 +9,11 @@
 namespace chromecast {
 
 AuraComponents::AuraComponents(CastWindowManager* cast_window_manager)
-    : media_overlay_(std::make_unique<MediaOverlayImpl>(cast_window_manager)) {}
+#if defined(ENABLE_MEDIA_OVERLAY)
+    : media_overlay_(std::make_unique<MediaOverlayImpl>(cast_window_manager))
+#endif
+{
+}
 
 AuraComponents::~AuraComponents() = default;