Remove all C++ Telemetry Accumulation calls.

This creates a number of stubs and leaves some surrounding code that may be irrelevant (eg. recorded time stamps, status variables).
Stub resolution/removal should be a follow-up to this.

dom/media/eme/DetailedPromise.cpp

@@ -96,9 +96,6 @@ DetailedPromise::MaybeReportTelemetry(Status aStatus)
   uint32_t latency = (TimeStamp::Now() - mStartTime).ToMilliseconds();
   EME_LOG("%s %s latency %ums reported via telemetry", mName.get(),
           ((aStatus == Succeeded) ? "succcess" : "failure"), latency);
-  Telemetry::ID tid = (aStatus == Succeeded) ? mSuccessLatencyProbe.Value()
-                                             : mFailureLatencyProbe.Value();
-  Telemetry::Accumulate(tid, latency);
 }
 
 } // namespace dom

dom/media/eme/MediaKeySession.cpp

@@ -315,9 +315,6 @@ MediaKeySession::GenerateRequest(const nsAString& aInitDataType,
 
   // Note: Remaining steps of generateRequest method continue in CDM.
 
-  Telemetry::Accumulate(Telemetry::VIDEO_CDM_GENERATE_REQUEST_CALLED,
-                        ToCDMTypeTelemetryEnum(mKeySystem));
-
   // Convert initData to base64 for easier logging.
   // Note: CreateSession() Move()s the data out of the array, so we have
   // to copy it here.

dom/media/eme/MediaKeys.cpp

@@ -13,7 +13,6 @@
 #include "mozilla/dom/MediaKeySession.h"
 #include "mozilla/dom/DOMException.h"
 #include "mozilla/dom/UnionTypes.h"
-#include "mozilla/Telemetry.h"
 #include "GMPCDMProxy.h"
 #ifdef MOZ_WIDGET_ANDROID
 #include "mozilla/MediaDrmCDMProxy.h"
@@ -457,7 +456,6 @@ MediaKeys::OnCDMCreated(PromiseId aId, const nsACString& aNodeId, const uint32_t
                                         mKeySystem,
                                         MediaKeySystemStatus::Cdm_created);
 
-  Telemetry::Accumulate(Telemetry::VIDEO_CDM_CREATED, ToCDMTypeTelemetryEnum(mKeySystem));
 }
 
 static bool