--- a/browser/components/nsBrowserGlue.js
+++ b/browser/components/nsBrowserGlue.js
@@ -754,34 +754,20 @@ BrowserGlue.prototype = {
     ];
 
     let nb = win.document.getElementById("high-priority-global-notificationbox");
     nb.appendNotification(message, "unsigned-addons-disabled", "",
                           nb.PRIORITY_WARNING_MEDIUM, buttons);
   },
 
   _firstWindowTelemetry(aWindow) {
-    let SCALING_PROBE_NAME = "";
-    switch (AppConstants.platform) {
-      case "win":
-        SCALING_PROBE_NAME = "DISPLAY_SCALING_MSWIN";
-        break;
-      case "macosx":
-        SCALING_PROBE_NAME = "DISPLAY_SCALING_OSX";
-        break;
-      case "linux":
-        SCALING_PROBE_NAME = "DISPLAY_SCALING_LINUX";
-        break;
-    }
-    if (SCALING_PROBE_NAME) {
-      let scaling = aWindow.devicePixelRatio * 100;
-      try {
-        Services.telemetry.getHistogramById(SCALING_PROBE_NAME).add(scaling);
-      } catch (ex) {}
-    }
+    let scaling = aWindow.devicePixelRatio * 100;
+    try {
+      Services.telemetry.getHistogramById("DISPLAY_SCALING").add(scaling);
+    } catch (ex) {}
   },
 
   // the first browser window has finished initializing
   _onFirstWindowLoaded: function BG__onFirstWindowLoaded(aWindow) {
     // Initialize PdfJs when running in-process and remote. This only
     // happens once since PdfJs registers global hooks. If the PdfJs
     // extension is installed the init method below will be overridden
     // leaving initialization to the extension.

--- a/toolkit/components/telemetry/Histograms.json
+++ b/toolkit/components/telemetry/Histograms.json
@@ -9432,39 +9432,24 @@
     "n_values": 30,
     "description": "Algorithms used with WebCrypto (see table in WebCryptoTask.cpp)"
   },
   "MASTER_PASSWORD_ENABLED": {
     "expires_in_version": "never",
     "kind": "flag",
     "description": "If a master-password is enabled for this profile"
   },
-  "DISPLAY_SCALING_OSX" : {
-    "expires_in_version": "never",
-    "kind": "linear",
-    "high": 500,
-    "n_buckets": 100,
-    "description": "Scaling percentage for the display where the first window is opened (OS X only)",
-    "cpp_guard": "XP_MACOSX"
-  },
-  "DISPLAY_SCALING_MSWIN" : {
+  "DISPLAY_SCALING" : {
     "expires_in_version": "never",
     "kind": "linear",
     "high": 500,
     "n_buckets": 100,
-    "description": "Scaling percentage for the display where the first window is opened (MS Windows only)",
-    "cpp_guard": "XP_WIN"
-  },
-  "DISPLAY_SCALING_LINUX" : {
-    "expires_in_version": "never",
-    "kind": "linear",
-    "high": 500,
-    "n_buckets": 100,
-    "description": "Scaling percentage for the display where the first window is opened (Linux only)",
-    "cpp_guard": "XP_LINUX"
+    "bug_numbers": [1121966],
+    "alert_emails": ["dolske@mozilla.com"],
+    "description": "Scaling percentage for the display where the first window is opened"
   },
   "SOCIAL_SIDEBAR_STATE": {
     "expires_in_version": "never",
     "kind": "boolean",
     "description": "Social Sidebar state 0: closed, 1: opened.  Toggling between providers will result in a higher opened rate."
   },
   "SOCIAL_TOOLBAR_BUTTONS": {
     "expires_in_version": "never",

--- a/toolkit/components/telemetry/histogram-whitelists.json
+++ b/toolkit/components/telemetry/histogram-whitelists.json
@@ -200,19 +200,16 @@
     "DEVTOOLS_WEBIDE_LOCAL_CONNECTION_RESULT",
     "DEVTOOLS_WEBIDE_OTHER_CONNECTION_RESULT",
     "DEVTOOLS_WEBIDE_PROJECT_EDITOR_TIME_ACTIVE_SECONDS",
     "DEVTOOLS_WEBIDE_REMOTE_CONNECTION_RESULT",
     "DEVTOOLS_WEBIDE_SIMULATOR_CONNECTION_RESULT",
     "DEVTOOLS_WEBIDE_TIME_ACTIVE_SECONDS",
     "DEVTOOLS_WEBIDE_USB_CONNECTION_RESULT",
     "DEVTOOLS_WEBIDE_WIFI_CONNECTION_RESULT",
-    "DISPLAY_SCALING_LINUX",
-    "DISPLAY_SCALING_MSWIN",
-    "DISPLAY_SCALING_OSX",
     "DNS_BLACKLIST_COUNT",
     "DNS_CLEANUP_AGE",
     "DNS_FAILED_LOOKUP_TIME",
     "DNS_LOOKUP_METHOD2",
     "DNS_LOOKUP_TIME",
     "DNS_RENEWAL_TIME",
     "DNS_RENEWAL_TIME_FOR_TTL",
     "DNT_USAGE",
@@ -876,19 +873,16 @@
     "DEVTOOLS_WEBIDE_LOCAL_CONNECTION_RESULT",
     "DEVTOOLS_WEBIDE_OTHER_CONNECTION_RESULT",
     "DEVTOOLS_WEBIDE_PROJECT_EDITOR_TIME_ACTIVE_SECONDS",
     "DEVTOOLS_WEBIDE_REMOTE_CONNECTION_RESULT",
     "DEVTOOLS_WEBIDE_SIMULATOR_CONNECTION_RESULT",
     "DEVTOOLS_WEBIDE_TIME_ACTIVE_SECONDS",
     "DEVTOOLS_WEBIDE_USB_CONNECTION_RESULT",
     "DEVTOOLS_WEBIDE_WIFI_CONNECTION_RESULT",
-    "DISPLAY_SCALING_LINUX",
-    "DISPLAY_SCALING_MSWIN",
-    "DISPLAY_SCALING_OSX",
     "DNS_BLACKLIST_COUNT",
     "DNS_CLEANUP_AGE",
     "DNS_FAILED_LOOKUP_TIME",
     "DNS_LOOKUP_METHOD2",
     "DNS_LOOKUP_TIME",
     "DNS_RENEWAL_TIME",
     "DNS_RENEWAL_TIME_FOR_TTL",
     "DNT_USAGE",