Allow 4hz framerate on headless devices

Allows 4hz framerate on headless devices with kReduceHeadlessFrameRate
feature

Bug: b/139299756
Test: Compile cast_shell for headless device
Change-Id: I13a36cbc2225c20367188375518b34baf585f2df
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1815049
Commit-Queue: Shawn Gallea <sagallea@google.com>
Reviewed-by: Michael Spang <spang@chromium.org>
Reviewed-by: Sunny Sachanandani <sunnyps@chromium.org>
Cr-Commit-Position: refs/heads/master@{#706035}

chromecast/base/cast_features.cc

@@ -158,6 +158,10 @@ const base::Feature kUseQueryableDataBackend{"use_queryable_data_backend",
 const base::Feature kEnableSideGesturePassThrough{
     "enable_side_gesture_pass_through", base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Lowers frame rate for headless
+const base::Feature kReduceHeadlessFrameRate{"reduce_headless_frame_rate",
+                                             base::FEATURE_DISABLED_BY_DEFAULT};
+
 // End Chromecast Feature definitions.
 const base::Feature* kFeatures[] = {
     &kAllowUserMediaAccess,
@@ -168,6 +172,7 @@ const base::Feature* kFeatures[] = {
     &kEnableGeneralAudienceBrowsing,
     &kUseQueryableDataBackend,
     &kEnableSideGesturePassThrough,
+    &kReduceHeadlessFrameRate,
 };
 
 // An iterator for a base::DictionaryValue. Use an alias for brevity in loops.

chromecast/base/cast_features.h

@@ -31,6 +31,7 @@ extern const base::Feature kDisableIdleSocketsCloseOnMemoryPressure;
 extern const base::Feature kEnableGeneralAudienceBrowsing;
 extern const base::Feature kUseQueryableDataBackend;
 extern const base::Feature kEnableSideGesturePassThrough;
+extern const base::Feature kReduceHeadlessFrameRate;
 
 // Get an iterable list of all of the cast features for checking all features as
 // a collection.

chromecast/graphics/BUILD.gn

@@ -69,6 +69,7 @@ cast_source_set("graphics") {
     ]
 
     deps += [
+      "//chromecast:chromecast_buildflags",
       "//components/viz/common",
       "//ui/base/ime/init",
       "//ui/events:gesture_detection",

chromecast/graphics/cast_window_manager_aura.cc

@@ -4,9 +4,11 @@
 
 #include "chromecast/graphics/cast_window_manager_aura.h"
 
+#include "base/feature_list.h"
 #include "base/memory/ptr_util.h"
 #include "build/build_config.h"
 #include "chromecast/base/cast_features.h"
+#include "chromecast/chromecast_buildflags.h"
 #include "chromecast/graphics/cast_focus_client_aura.h"
 #include "chromecast/graphics/cast_touch_activity_observer.h"
 #include "chromecast/graphics/cast_touch_event_gate.h"
@@ -254,6 +256,14 @@ void CastWindowManagerAura::Setup() {
     side_swipe_detector_ = std::make_unique<SideSwipeDetector>(
         system_gesture_dispatcher_.get(), root_window);
   }
+
+#if BUILDFLAG(IS_CAST_AUDIO_ONLY)
+  if (base::FeatureList::IsEnabled(kReduceHeadlessFrameRate)) {
+    ui::Compositor* compositor = window_tree_host_->compositor();
+    compositor->SetDisplayVSyncParameters(
+        base::TimeTicks(), base::TimeDelta::FromMilliseconds(250));
+  }
+#endif
 }
 
 void CastWindowManagerAura::OnWindowOrderChanged(