--- a/devtools/shared/webconsole/network-monitor.js
+++ b/devtools/shared/webconsole/network-monitor.js
@@ -422,58 +422,19 @@ NetworkResponseListener.prototype = {
   /**
    * See documentation at
    * https://developer.mozilla.org/En/NsIRequestObserver
    *
    * @param nsIRequest request
    * @param nsISupports context
    */
   onStartRequest: function (request) {
-    // Converter will call this again, we should just ignore that.
-    if (this.request) {
-      return;
-    }
-
     this.request = request;
     this._getSecurityInfo();
     this._findOpenResponse();
-    // We need to track the offset for the onDataAvailable calls where
-    // we pass the data from our pipe to the converter.
-    this.offset = 0;
-
-    // In the multi-process mode, the conversion happens on the child
-    // side while we can only monitor the channel on the parent
-    // side. If the content is gzipped, we have to unzip it
-    // ourself. For that we use the stream converter services.  Do not
-    // do that for Service workers as they are run in the child
-    // process.
-    let channel = this.request;
-    if (!this.httpActivity.fromServiceWorker &&
-        channel instanceof Ci.nsIEncodedChannel &&
-        channel.contentEncodings &&
-        !channel.applyConversion) {
-      let encodingHeader = channel.getResponseHeader("Content-Encoding");
-      let scs = Cc["@mozilla.org/streamConverters;1"]
-        .getService(Ci.nsIStreamConverterService);
-      let encodings = encodingHeader.split(/\s*\t*,\s*\t*/);
-      let nextListener = this;
-      let acceptedEncodings = ["gzip", "deflate", "br", "x-gzip", "x-deflate"];
-      for (let i in encodings) {
-        // There can be multiple conversions applied
-        let enc = encodings[i].toLowerCase();
-        if (acceptedEncodings.indexOf(enc) > -1) {
-          this.converter = scs.asyncConvertData(enc, "uncompressed",
-                                                nextListener, null);
-          nextListener = this.converter;
-        }
-      }
-      if (this.converter) {
-        this.converter.onStartRequest(this.request, null);
-      }
-    }
     // Asynchronously wait for the data coming from the request.
     this.setAsyncListener(this.sink.inputStream, this);
   },
 
   /**
    * Parse security state of this request and report it to the client.
    */
   _getSecurityInfo: DevToolsUtils.makeInfallible(function () {
@@ -629,17 +590,16 @@ NetworkResponseListener.prototype = {
       response,
       this.httpActivity.discardResponseBody
     );
 
     this._wrappedNotificationCallbacks = null;
     this.httpActivity = null;
     this.sink = null;
     this.inputStream = null;
-    this.converter = null;
     this.request = null;
     this.owner = null;
   },
 
   /**
    * The nsIInputStreamCallback for when the request input stream is ready -
    * either it has more data or it is closed.
    *
@@ -657,25 +617,21 @@ NetworkResponseListener.prototype = {
       // This may throw if the stream is closed normally or due to an error.
       available = stream.available();
     } catch (ex) {
       // Ignore.
     }
 
     if (available != -1) {
       if (available != 0) {
-        if (this.converter) {
-          this.converter.onDataAvailable(this.request, null, stream,
-                                         this.offset, available);
-        } else {
-          this.onDataAvailable(this.request, null, stream, this.offset,
-                               available);
-        }
+        // Note that passing 0 as the offset here is wrong, but the
+        // onDataAvailable() method does not use the offset, so it does not
+        // matter.
+        this.onDataAvailable(this.request, null, stream, 0, available);
       }
-      this.offset += available;
       this.setAsyncListener(stream, this);
     } else {
       this.onStreamClose();
       this.offset = 0;
     }
   },
 };