Bug 1705007: Ensure GPU process has created the observer service. r=gfx-reviewers,aosmond

Differential Revision: https://phabricator.services.mozilla.com/D113193

gfx/ipc/GPUParent.cpp

@@ -28,6 +28,7 @@
 #include "mozilla/HangDetails.h"
 #include "mozilla/PerfStats.h"
 #include "mozilla/Preferences.h"
+#include "mozilla/ProcessPriorityManager.h"
 #include "mozilla/RemoteDecoderManagerChild.h"
 #include "mozilla/RemoteDecoderManagerParent.h"
 #include "mozilla/ScopeExit.h"
@@ -167,6 +168,9 @@ bool GPUParent::Init(base::ProcessId aParentPid, const char* aParentBuildID,
     return false;
   }
 
+  // Ensure the observer service exists.
+  ProcessPriorityManager::Init();
+
   // Init crash reporter support.
   CrashReporterClient::InitSingleton(this);