Bug 1836191 - remove ChromeUtils.requestPerformanceMetrics that was only used by about:performance, r=smaug.

Differential Revision: https://phabricator.services.mozilla.com/D179696

dom/base/ChromeUtils.cpp

@@ -23,7 +23,6 @@
 #include "mozilla/EventStateManager.h"
 #include "mozilla/FormAutofillNative.h"
 #include "mozilla/IntentionalCrash.h"
-#include "mozilla/PerformanceMetricsCollector.h"
 #include "mozilla/PerfStats.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/ProcInfo.h"
@@ -1475,35 +1474,6 @@ bool ChromeUtils::VsyncEnabled(GlobalObject& aGlobal) {
   return mozilla::gfx::VsyncSource::GetFastestVsyncRate().isSome();
 }
 
-/* static */
-already_AddRefed<Promise> ChromeUtils::RequestPerformanceMetrics(
-    GlobalObject& aGlobal, ErrorResult& aRv) {
-  MOZ_ASSERT(XRE_IsParentProcess());
-
-  // Creating a JS promise
-  nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(aGlobal.GetAsSupports());
-  MOZ_ASSERT(global);
-  RefPtr<Promise> domPromise = Promise::Create(global, aRv);
-  if (NS_WARN_IF(aRv.Failed())) {
-    return nullptr;
-  }
-  MOZ_ASSERT(domPromise);
-  RefPtr<nsISerialEventTarget> target =
-      global->EventTargetFor(TaskCategory::Performance);
-
-  // requesting metrics, that will be returned into the promise
-  PerformanceMetricsCollector::RequestMetrics()->Then(
-      target, __func__,
-      [domPromise,
-       target](nsTArray<dom::PerformanceInfoDictionary>&& aResults) {
-        domPromise->MaybeResolve(std::move(aResults));
-      },
-      [domPromise](const nsresult& aRv) { domPromise->MaybeReject(aRv); });
-
-  // sending back the promise instance
-  return domPromise.forget();
-}
-
 void ChromeUtils::SetPerfStatsCollectionMask(GlobalObject& aGlobal,
                                              uint64_t aMask) {
   PerfStats::SetCollectionMask(static_cast<PerfStats::MetricMask>(aMask));