diff --git a/toolkit/components/telemetry/TelemetryPing.js b/toolkit/components/telemetry/TelemetryPing.js
index 6b4b739934c..a694eb5fd00 100644
--- a/toolkit/components/telemetry/TelemetryPing.js
+++ b/toolkit/components/telemetry/TelemetryPing.js
@@ -104,7 +104,7 @@ function generateUUID() {
 
 /**
  * Read current process I/O counters.
- */            
+ */
 let processInfo = {
   _initialized: false,
   _IO_COUNTERS: null,
@@ -128,23 +128,23 @@ let processInfo = {
         {'otherBytes': ctypes.unsigned_long_long} ]);
       try {
         this._kernel32 = ctypes.open("Kernel32.dll");
-        this._GetProcessIoCounters = this._kernel32.declare("GetProcessIoCounters", 
+        this._GetProcessIoCounters = this._kernel32.declare("GetProcessIoCounters",
           ctypes.winapi_abi,
           ctypes.bool, // return
           ctypes.voidptr_t, // hProcess
           this._IO_COUNTERS.ptr); // lpIoCounters
-        this._GetCurrentProcess = this._kernel32.declare("GetCurrentProcess", 
+        this._GetCurrentProcess = this._kernel32.declare("GetCurrentProcess",
           ctypes.winapi_abi,
           ctypes.voidptr_t); // return
         this._initialized = true;
-      } catch (err) { 
-        return null; 
+      } catch (err) {
+        return null;
       }
     }
     let io = new this._IO_COUNTERS();
     if(!this._GetProcessIoCounters(this._GetCurrentProcess(), io.address()))
       return null;
-    return [parseInt(io.readBytes), parseInt(io.writeBytes)];  
+    return [parseInt(io.readBytes), parseInt(io.writeBytes)];
   }
 };
 
@@ -172,7 +172,7 @@ TelemetryPing.prototype = {
   /**
    * Gets a series of simple measurements (counters). At the moment, this
    * only returns startup data from nsIAppStartup.getStartupInfo().
-   * 
+   *
    * @return simple measurements as a dictionary.
    */
   getSimpleMeasurements: function getSimpleMeasurements(forSavedSession) {
@@ -251,12 +251,12 @@ TelemetryPing.prototype = {
   /**
    * When reflecting a histogram into JS, Telemetry hands us an object
    * with the following properties:
-   * 
+   *
    * - min, max, histogram_type, sum, sum_squares_{lo,hi}: simple integers;
    * - log_sum, log_sum_squares: doubles;
    * - counts: array of counts for histogram buckets;
    * - ranges: array of calculated bucket sizes.
-   * 
+   *
    * This format is not straightforward to read and potentially bulky
    * with lots of zeros in the counts array.  Packing histograms makes
    * raw histograms easier to read and compresses the data a little bit.
@@ -344,18 +344,9 @@ TelemetryPing.prototype = {
     return ret;
   },
 
-  addValue: function addValue(name, id, val) {
-    let h = this._histograms[name];
-    if (!h) {
-      h = Telemetry.getHistogramById(id);
-      this._histograms[name] = h;
-    }
-    h.add(val);
-  },
-
   /**
    * Descriptive metadata
-   * 
+   *
    * @param  reason
    *         The reason for the telemetry ping, this will be included in the
    *         returned metadata,
@@ -477,7 +468,7 @@ TelemetryPing.prototype = {
 
         function h(process, path, kind, units, amount, desc) {
           if (!hasReported) {
-            boundHandleMemoryReport(id, path, units, amount);
+            boundHandleMemoryReport(id, units, amount);
             hasReported = true;
           } else {
             NS_ASSERT(false,
@@ -492,7 +483,7 @@ TelemetryPing.prototype = {
     histogram.add(new Date() - startTime);
   },
 
-  handleMemoryReport: function(id, path, units, amount) {
+  handleMemoryReport: function(id, units, amount) {
     let val;
     if (units == Ci.nsIMemoryReporter.UNITS_BYTES) {
       val = Math.floor(amount / 1024);
@@ -508,23 +499,28 @@ TelemetryPing.prototype = {
       // If the reporter gives us a cumulative count, we'll report the
       // difference in its value between now and our previous ping.
 
-      if (!(path in this._prevValues)) {
+      if (!(id in this._prevValues)) {
         // If this is the first time we're reading this reporter, store its
         // current value but don't report it in the telemetry ping, so we
         // ignore the effect startup had on the reporter.
-        this._prevValues[path] = amount;
+        this._prevValues[id] = amount;
         return;
       }
 
-      val = amount - this._prevValues[path];
-      this._prevValues[path] = amount;
+      val = amount - this._prevValues[id];
+      this._prevValues[id] = amount;
     }
     else {
       NS_ASSERT(false, "Can't handle memory reporter with units " + units);
       return;
     }
 
-    this.addValue(path, id, val);
+    let h = this._histograms[id];
+    if (!h) {
+      h = Telemetry.getHistogramById(id);
+      this._histograms[id] = h;
+    }
+    h.add(val);
   },
 
   /**
@@ -534,8 +530,8 @@ TelemetryPing.prototype = {
   isInterestingStartupHistogram: function isInterestingStartupHistogram(name) {
     return this._startupHistogramRegex.test(name);
   },
-  
-  /** 
+
+  /**
    * Make a copy of interesting histograms at startup.
    */
   gatherStartupHistograms: function gatherStartupHistograms() {
@@ -779,7 +775,7 @@ TelemetryPing.prototype = {
       return;
     }
 #endif
-    let enabled = false; 
+    let enabled = false;
     try {
       enabled = Services.prefs.getBoolPref(PREF_ENABLED);
       this._server = Services.prefs.getCharPref(PREF_SERVER);
@@ -835,12 +831,12 @@ TelemetryPing.prototype = {
   getFlashVersion: function getFlashVersion() {
     let host = Cc["@mozilla.org/plugin/host;1"].getService(Ci.nsIPluginHost);
     let tags = host.getPluginTags();
-    
+
     for (let i = 0; i < tags.length; i++) {
       if (tags[i].name == "Shockwave Flash")
         return tags[i].version;
     }
-    
+
     return null;
   },
 
@@ -855,7 +851,7 @@ TelemetryPing.prototype = {
       file, sync, true);
   },
 
-  /** 
+  /**
    * Remove observers to avoid leaks
    */
   uninstall: function uninstall() {
@@ -943,10 +939,10 @@ TelemetryPing.prototype = {
       break;
     case "xul-window-visible":
       Services.obs.removeObserver(this, "xul-window-visible");
-      this._hasXulWindowVisibleObserver = false;   
+      this._hasXulWindowVisibleObserver = false;
       var counters = processInfo.getCounters();
       if (counters) {
-        [this._startupIO.startupWindowVisibleReadBytes, 
+        [this._startupIO.startupWindowVisibleReadBytes,
           this._startupIO.startupWindowVisibleWriteBytes] = counters;
       }
       break;