--- a/devtools/server/actors/network-event.js
+++ b/devtools/server/actors/network-event.js
@@ -1,16 +1,17 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
 const protocol = require("devtools/shared/protocol");
 const { networkEventSpec } = require("devtools/shared/specs/network-event");
+const { LongStringActor } = require("devtools/server/actors/string");
 
 /**
  * Creates an actor for a network event.
  *
  * @constructor
  * @param object webConsoleActor
  *        The parent WebConsoleActor instance for this object.
  */
@@ -38,25 +39,21 @@ const NetworkEventActor = protocol.Actor
       content: {},
     };
 
     this._timings = {};
     this._stackTrace = {};
 
     this._discardRequestBody = false;
     this._discardResponseBody = false;
-
-    // Keep track of LongStringActors owned by this NetworkEventActor.
-    this._longStringActors = new Set();
   },
 
   _request: null,
   _response: null,
   _timings: null,
-  _longStringActors: null,
 
   /**
    * Returns a grip for this actor for returning in a protocol message.
    */
   form() {
     return {
       actor: this.actorID,
       startedDateTime: this._startedDateTime,
@@ -70,24 +67,16 @@ const NetworkEventActor = protocol.Actor
       private: this._private,
     };
   },
 
   /**
    * Releases this actor from the pool.
    */
   destroy(conn) {
-    for (let grip of this._longStringActors) {
-      let actor = this.webConsoleActor.getActorByID(grip.actor);
-      if (actor) {
-        this.webConsoleActor.releaseActor(actor);
-      }
-    }
-    this._longStringActors = new Set();
-
     if (!this.webConsoleActor) {
       return;
     }
     if (this._request.url) {
       this.webConsoleActor._networkEventActorsByURL.delete(this._request.url);
     }
     if (this.channel) {
       this.webConsoleActor._netEvents.delete(this.channel);
@@ -267,19 +256,18 @@ const NetworkEventActor = protocol.Actor
    *        The request headers array.
    * @param string rawHeaders
    *        The raw headers source.
    */
   addRequestHeaders(headers, rawHeaders) {
     this._request.headers = headers;
     this._prepareHeaders(headers);
 
-    rawHeaders = this.parent._createStringGrip(rawHeaders);
-    if (typeof rawHeaders == "object") {
-      this._longStringActors.add(rawHeaders);
+    if (rawHeaders) {
+      rawHeaders = new LongStringActor(this.conn, rawHeaders);
     }
     this._request.rawHeaders = rawHeaders;
 
     this.emit("network-event-update", "requestHeaders", {
       headers: headers.length,
       headersSize: this._request.headersSize,
     });
   },
@@ -302,40 +290,34 @@ const NetworkEventActor = protocol.Actor
   /**
    * Add network request POST data.
    *
    * @param object postData
    *        The request POST data.
    */
   addRequestPostData(postData) {
     this._request.postData = postData;
-    postData.text = this.parent._createStringGrip(postData.text);
-    if (typeof postData.text == "object") {
-      this._longStringActors.add(postData.text);
-    }
+    postData.text = new LongStringActor(this.conn, postData.text);
 
     this.emit("network-event-update", "requestPostData", {
-      dataSize: postData.text.length,
+      dataSize: postData.text.str.length,
       discardRequestBody: this._discardRequestBody,
     });
   },
 
   /**
    * Add the initial network response information.
    *
    * @param object info
    *        The response information.
    * @param string rawHeaders
    *        The raw headers source.
    */
   addResponseStart(info, rawHeaders) {
-    rawHeaders = this.parent._createStringGrip(rawHeaders);
-    if (typeof rawHeaders == "object") {
-      this._longStringActors.add(rawHeaders);
-    }
+    rawHeaders = new LongStringActor(this.conn, rawHeaders);
     this._response.rawHeaders = rawHeaders;
 
     this._response.httpVersion = info.httpVersion;
     this._response.status = info.status;
     this._response.statusText = info.statusText;
     this._response.headersSize = info.headersSize;
     // Consider as not discarded if info.discardResponseBody is undefined
     this._discardResponseBody = !!info.discardResponseBody;
@@ -399,20 +381,17 @@ const NetworkEventActor = protocol.Actor
    *        - boolean discardedResponseBody
    *          Tells if the response content was recorded or not.
    *        - boolean truncated
    *          Tells if the some of the response content is missing.
    */
   addResponseContent(content, {discardResponseBody, truncated}) {
     this._truncated = truncated;
     this._response.content = content;
-    content.text = this.parent._createStringGrip(content.text);
-    if (typeof content.text == "object") {
-      this._longStringActors.add(content.text);
-    }
+    content.text = new LongStringActor(this.conn, content.text);
 
     this.emit("network-event-update", "responseContent", {
       mimeType: content.mimeType,
       contentSize: content.size,
       encoding: content.encoding,
       transferredSize: content.transferredSize,
       discardResponseBody,
     });
@@ -440,17 +419,14 @@ const NetworkEventActor = protocol.Actor
    * Prepare the headers array to be sent to the client by using the
    * LongStringActor for the header values, when needed.
    *
    * @private
    * @param array aHeaders
    */
   _prepareHeaders(headers) {
     for (let header of headers) {
-      header.value = this.parent._createStringGrip(header.value);
-      if (typeof header.value == "object") {
-        this._longStringActors.add(header.value);
-      }
+      header.value = new LongStringActor(this.conn, header.value);
     }
   },
 });
 
 exports.NetworkEventActor = NetworkEventActor;

--- a/devtools/server/actors/stylesheets.js
+++ b/devtools/server/actors/stylesheets.js
@@ -470,30 +470,20 @@ var StyleSheetActor = protocol.ActorClas
     let request = consoleActor.getNetworkEventActorForURL(href);
     if (!request) {
       return null;
     }
     let content = request._response.content;
     if (request._discardResponseBody || request._truncated || !content) {
       return null;
     }
-    if (content.text.type != "longString") {
-      // For short strings, the text is available directly.
-      return {
-        content: content.text,
-        contentType: content.mimeType,
-      };
-    }
-    // For long strings, look up the actor that holds the full text.
-    let longStringActor = this.conn._getOrCreateActor(content.text.actor);
-    if (!longStringActor) {
-      return null;
-    }
+    // `content.text` is a LongStringActor instance
+    // Get a reference to the raw string via `str` property
     return {
-      content: longStringActor.rawValue(),
+      content: content.text.str,
       contentType: content.mimeType,
     };
   },
 
   /**
    * Protocol method to get the media rules for the stylesheet.
    */
   getMediaRules: function() {