--- a/browser/devtools/framework/gDevTools.jsm
+++ b/browser/devtools/framework/gDevTools.jsm
@@ -26,32 +26,33 @@ XPCOMUtils.defineLazyModuleGetter(this, 
 XPCOMUtils.defineLazyModuleGetter(this, "DebuggerClient",
                                   "resource://gre/modules/devtools/dbg-client.jsm");
 
 const EventEmitter = devtools.require("devtools/toolkit/event-emitter");
 const Telemetry = devtools.require("devtools/shared/telemetry");
 
 const TABS_OPEN_PEAK_HISTOGRAM = "DEVTOOLS_TABS_OPEN_PEAK_LINEAR";
 const TABS_OPEN_AVG_HISTOGRAM = "DEVTOOLS_TABS_OPEN_AVERAGE_LINEAR";
-const TABS_PINNED_PEAK_HISTOGRAM = "DEVTOOLS_TABS_PINNED_PEAK_EXPONENTIAL";
-const TABS_PINNED_AVG_HISTOGRAM = "DEVTOOLS_TABS_PINNED_AVERAGE_EXPONENTIAL";
+const TABS_PINNED_PEAK_HISTOGRAM = "DEVTOOLS_TABS_PINNED_PEAK_LINEAR";
+const TABS_PINNED_AVG_HISTOGRAM = "DEVTOOLS_TABS_PINNED_AVERAGE_LINEAR";
 
 const FORBIDDEN_IDS = new Set(["toolbox", ""]);
 const MAX_ORDINAL = 99;
 
 const bundle = Services.strings.createBundle("chrome://browser/locale/devtools/toolbox.properties");
 
 /**
  * DevTools is a class that represents a set of developer tools, it holds a
  * set of tools and keeps track of open toolboxes in the browser.
  */
 this.DevTools = function DevTools() {
   this._tools = new Map();     // Map<toolId, tool>
   this._themes = new Map();    // Map<themeId, theme>
   this._toolboxes = new Map(); // Map<target, toolbox>
+  this._telemetry = new Telemetry();
 
   // destroy() is an observer's handler so we need to preserve context.
   this.destroy = this.destroy.bind(this);
   this._teardown = this._teardown.bind(this);
 
   this._testing = false;
 
   EventEmitter.decorate(this);

--- a/toolkit/components/telemetry/Histograms.json
+++ b/toolkit/components/telemetry/Histograms.json
@@ -6566,26 +6566,26 @@
   },
   "DEVTOOLS_TABS_OPEN_PEAK_LINEAR": {
     "expires_in_version": "never",
     "kind": "linear",
     "high": "101",
     "n_buckets": 100,
     "description": "The peak number of open tabs in all windows for a session for devtools users."
   },
-  "DEVTOOLS_TABS_OPEN_AVERAGE_EXPONENTIAL": {
-    "expires_in_version": "never",
-    "kind": "exponential",
+  "DEVTOOLS_TABS_OPEN_AVERAGE_LINEAR": {
+    "expires_in_version": "never",
+    "kind": "linear",
     "high": "101",
     "n_buckets": "100",
     "description": "The mean number of open tabs in all windows for a session for devtools users."
   },
-  "DEVTOOLS_TABS_PINNED_PEAK_EXPONENTIAL": {
-    "expires_in_version": "never",
-    "kind": "exponential",
+  "DEVTOOLS_TABS_PINNED_PEAK_LINEAR": {
+    "expires_in_version": "never",
+    "kind": "linear",
     "high": "101",
     "n_buckets": "100",
     "description": "The peak number of pinned tabs (app tabs) in all windows for a session for devtools users."
   },
   "DEVTOOLS_TABS_PINNED_AVERAGE_LINEAR": {
     "expires_in_version": "never",
     "kind": "linear",
     "high": "101",