--- a/dom/media/gmp/ChromiumCDMParent.cpp
+++ b/dom/media/gmp/ChromiumCDMParent.cpp
@@ -11,17 +11,16 @@
 #include "content_decryption_module.h"
 #include "GMPContentChild.h"
 #include "GMPContentParent.h"
 #include "GMPLog.h"
 #include "GMPUtils.h"
 #include "MediaPrefs.h"
 #include "mozilla/dom/MediaKeyMessageEventBinding.h"
 #include "mozilla/gmp/GMPTypes.h"
-#include "mozilla/Telemetry.h"
 #include "mozilla/Unused.h"
 #include "AnnexB.h"
 #include "H264.h"
 
 #define NS_DispatchToMainThread(...) CompileError_UseAbstractMainThreadInstead
 
 namespace mozilla {
 namespace gmp {
@@ -671,19 +670,16 @@ ChromiumCDMParent::EnsureSufficientShmem
 
   while (mVideoShmemsActive < mVideoShmemLimit) {
     if (!SendBufferToCDM(mVideoFrameBufferSize)) {
       return false;
     }
     mVideoShmemsActive++;
   }
 
-  mMaxVideoShmemsActive =
-    std::max(mMaxVideoShmemsActive, mVideoShmemsActive);
-
   return true;
 }
 
 ipc::IPCResult
 ChromiumCDMParent::RecvDecodedData(const CDMVideoFrame& aFrame,
                                    nsTArray<uint8_t>&& aData)
 {
   GMP_LOG("ChromiumCDMParent::RecvDecodedData(this=%p) time=%" PRId64,
@@ -1072,22 +1068,17 @@ ChromiumCDMParent::ShutdownVideoDecoder(
                                           __func__);
   mDecodePromise.RejectIfExists(NS_ERROR_DOM_MEDIA_CANCELED, __func__);
   MOZ_ASSERT(mFlushDecoderPromise.IsEmpty());
   if (!SendDeinitializeVideoDecoder()) {
     return ShutdownPromise::CreateAndResolve(true, __func__);
   }
   mVideoDecoderInitialized = false;
 
-  GMP_LOG("ChromiumCDMParent::~ShutdownVideoDecoder(this=%p) "
-          "VIDEO_CHROMIUM_CDM_MAX_SHMEMS=%u",
-          this,
-          mMaxVideoShmemsActive);
-  Telemetry::Accumulate(Telemetry::HistogramID::VIDEO_CHROMIUM_CDM_MAX_SHMEMS,
-                        mMaxVideoShmemsActive);
+  GMP_LOG("ChromiumCDMParent::~ShutdownVideoDecoder(this=%p) ", this);
 
   // The ChromiumCDMChild will purge its shmems, so if the decoder is
   // reinitialized the shmems need to be re-allocated, and they may need
   // to be a different size.
   mVideoShmemsActive = 0;
   mVideoFrameBufferSize = 0;
   return ShutdownPromise::CreateAndResolve(true, __func__);
 }

--- a/dom/media/gmp/ChromiumCDMParent.h
+++ b/dom/media/gmp/ChromiumCDMParent.h
@@ -173,18 +173,16 @@ protected:
 
   size_t mVideoFrameBufferSize = 0;
 
   // Count of the number of shmems in the set used to return decoded video
   // frames from the CDM to Gecko.
   uint32_t mVideoShmemsActive = 0;
   // Maximum number of shmems to use to return decoded video frames.
   uint32_t mVideoShmemLimit;
-  // High water mark for mVideoShmemsActive, reported via telemetry.
-  uint32_t mMaxVideoShmemsActive = 0;
 
   bool mIsShutdown = false;
   bool mVideoDecoderInitialized = false;
   bool mActorDestroyed = false;
 
   // The H.264 decoder in Widevine CDM versions 970 and later output in decode
   // order rather than presentation order, so we reorder in presentation order
   // before presenting. mMaxRefFrames is non-zero if we have an initialized

--- a/toolkit/components/telemetry/Histograms.json
+++ b/toolkit/components/telemetry/Histograms.json
@@ -8570,25 +8570,16 @@
   "MEDIA_EME_SECURE_CONTEXT": {
     "record_in_processes": ["main", "content"],
     "alert_emails": ["cpearce@mozilla.com"],
     "expires_in_version": "60",
     "kind": "boolean",
     "description": "Reports whether a navigator.requestMediaKeySystemAccess() was called in a secure context (i.e. on an origin served over HTTPS) or not.",
     "bug_numbers": [1360438]
   },
-  "VIDEO_CHROMIUM_CDM_MAX_SHMEMS": {
-    "record_in_processes": ["main", "content"],
-    "alert_emails": ["cpearce@mozilla.com"],
-    "bug_numbers": [1366639],
-    "expires_in_version": "60",
-    "kind": "enumerated",
-    "n_values": 50,
-    "description": "Counts of the maximum number of shared memory buffers used for transferring video frames between the CDM and Gecko processes during playback of DRM'd video. Reported once per CDMVideoDecoder instance, i.e., once per JavaScript SourceBuffer during playback of video using EME."
-  },
   "MEDIA_EME_REQUEST_DEPRECATED_WARNINGS": {
     "record_in_processes": ["main", "content"],
     "alert_emails": ["cpearce@mozilla.com"],
     "bug_numbers": [1368596],
     "expires_in_version": "60",
     "kind": "enumerated",
     "n_values": 10,
     "description": "Counts types of deprecation warnings logged on every successful call to navigator.requestMediaKeySystemAccess(). 0=No warnings logged, 1=MediaEMENoCapabilitiesDeprecatedWarning, 2=MediaEMENoCodecsDeprecatedWarning."