diff --git a/browser/extensions/pdfjs/content/PdfJs.jsm b/browser/extensions/pdfjs/content/PdfJs.jsm
index 0ba78ff558bd..07fac75e3270 100644
--- a/browser/extensions/pdfjs/content/PdfJs.jsm
+++ b/browser/extensions/pdfjs/content/PdfJs.jsm
@@ -127,11 +127,20 @@ Factory.prototype = {
     var registrar = Cm.QueryInterface(Ci.nsIComponentRegistrar);
     registrar.registerFactory(proto.classID, proto.classDescription,
                               proto.contractID, factory);
+
+    if (proto.classID2) {
+      this._classID2 = proto.classID2;
+      registrar.registerFactory(proto.classID2, proto.classDescription,
+                                proto.contractID2, factory);
+    }
   },
 
   unregister: function unregister() {
     var registrar = Cm.QueryInterface(Ci.nsIComponentRegistrar);
     registrar.unregisterFactory(this._classID, this._factory);
+    if (this._classID2) {
+      registrar.unregisterFactory(this._classID2, this._factory);
+    }
     this._factory = null;
   }
 };
@@ -320,13 +329,6 @@ let PdfJs = {
     Cu.import('resource://pdf.js/PdfStreamConverter.jsm');
     this._pdfStreamConverterFactory.register(PdfStreamConverter);
 
-    this._pdfRedirectorFactory = new Factory();
-    Cu.import('resource://pdf.js/PdfRedirector.jsm');
-    this._pdfRedirectorFactory.register(PdfRedirector);
-
-    Svc.pluginHost.registerPlayPreviewMimeType(PDF_CONTENT_TYPE, true,
-      'data:application/x-moz-playpreview-pdfjs;,');
-
     this._registered = true;
   },
 
@@ -338,12 +340,6 @@ let PdfJs = {
     Cu.unload('resource://pdf.js/PdfStreamConverter.jsm');
     delete this._pdfStreamConverterFactory;
 
-    this._pdfRedirectorFactory.unregister();
-    Cu.unload('resource://pdf.js/PdfRedirector.jsm');
-    delete this._pdfRedirectorFactory;
-
-    Svc.pluginHost.unregisterPlayPreviewMimeType(PDF_CONTENT_TYPE);
-
     this._registered = false;
   }
 };
diff --git a/browser/extensions/pdfjs/content/PdfStreamConverter.jsm b/browser/extensions/pdfjs/content/PdfStreamConverter.jsm
index cce6d276b2f0..54bc9a6c1be1 100644
--- a/browser/extensions/pdfjs/content/PdfStreamConverter.jsm
+++ b/browser/extensions/pdfjs/content/PdfStreamConverter.jsm
@@ -813,6 +813,9 @@ PdfStreamConverter.prototype = {
   classDescription: 'pdf.js Component',
   contractID: '@mozilla.org/streamconv;1?from=application/pdf&to=*/*',
 
+  classID2: Components.ID('{d0c5195d-e798-49d4-b1d3-9324328b2292}'),
+  contractID2: '@mozilla.org/streamconv;1?from=application/pdf&to=text/html',
+
   QueryInterface: XPCOMUtils.generateQI([
       Ci.nsISupports,
       Ci.nsIStreamConverter,
diff --git a/docshell/base/nsWebNavigationInfo.cpp b/docshell/base/nsWebNavigationInfo.cpp
index 95ef8d950d03..c4d81ba8137a 100644
--- a/docshell/base/nsWebNavigationInfo.cpp
+++ b/docshell/base/nsWebNavigationInfo.cpp
@@ -44,6 +44,13 @@ nsWebNavigationInfo::IsTypeSupported(const nsACString& aType,
   // to say for itself.
   *aIsTypeSupported = nsIWebNavigationInfo::UNSUPPORTED;
 
+  // We want to claim that the type for PDF documents is unsupported,
+  // so that the internal PDF viewer's stream converted will get used.
+  if (aType.LowerCaseEqualsLiteral("application/pdf") &&
+      nsContentUtils::IsPDFJSEnabled()) {
+    return NS_OK;
+  }
+
   const nsCString& flatType = PromiseFlatCString(aType);
   nsresult rv = IsTypeSupportedInternal(flatType, aIsTypeSupported);
   NS_ENSURE_SUCCESS(rv, rv);
diff --git a/dom/base/nsContentUtils.cpp b/dom/base/nsContentUtils.cpp
index d8d661676007..2b00b491b6e5 100644
--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -152,6 +152,7 @@
 #include "nsIScriptGlobalObject.h"
 #include "nsIScriptObjectPrincipal.h"
 #include "nsIScriptSecurityManager.h"
+#include "nsIStreamConverterService.h"
 #include "nsIStringBundle.h"
 #include "nsIURI.h"
 #include "nsIURL.h"
@@ -6500,6 +6501,19 @@ nsContentUtils::AllowXULXBLForPrincipal(nsIPrincipal* aPrincipal)
           IsSitePermAllow(aPrincipal, "allowXULXBL"));
 }
 
+bool
+nsContentUtils::IsPDFJSEnabled()
+{
+   nsCOMPtr<nsIStreamConverterService> convServ =
+     do_GetService("@mozilla.org/streamConverters;1");
+   nsresult rv = NS_ERROR_FAILURE;
+   bool canConvert = false;
+   if (convServ) {
+     rv = convServ->CanConvert("application/pdf", "text/html", &canConvert);
+   }
+   return NS_SUCCEEDED(rv) && canConvert;
+}
+
 already_AddRefed<nsIDocumentLoaderFactory>
 nsContentUtils::FindInternalContentViewer(const nsACString& aType,
                                           ContentViewerType* aLoaderType)
@@ -7922,4 +7936,4 @@ nsContentUtils::SetFetchReferrerURIWithPolicy(nsIPrincipal* aPrincipal,
 
   net::ReferrerPolicy referrerPolicy = aDoc->GetReferrerPolicy();
   return aChannel->SetReferrerWithPolicy(referrerURI, referrerPolicy);
-}
\ No newline at end of file
+}
diff --git a/dom/base/nsContentUtils.h b/dom/base/nsContentUtils.h
index 437711af10cd..a7dd9289da79 100644
--- a/dom/base/nsContentUtils.h
+++ b/dom/base/nsContentUtils.h
@@ -2070,6 +2070,11 @@ public:
    */
   static void XPCOMShutdown();
 
+  /**
+   * Checks if internal PDF viewer is enabled.
+   */
+  static bool IsPDFJSEnabled();
+
   enum ContentViewerType
   {
       TYPE_UNSUPPORTED,
diff --git a/dom/base/nsObjectLoadingContent.cpp b/dom/base/nsObjectLoadingContent.cpp
index 5124a51e0f39..4af1e8eb84f2 100644
--- a/dom/base/nsObjectLoadingContent.cpp
+++ b/dom/base/nsObjectLoadingContent.cpp
@@ -552,6 +552,11 @@ IsPluginEnabledByExtension(nsIURI* uri, nsCString& mimeType)
     return false;
   }
 
+  // Disables any native PDF plugins, when internal PDF viewer is enabled.
+  if (ext.EqualsIgnoreCase("pdf") && nsContentUtils::IsPDFJSEnabled()) {
+    return false;
+  }
+
   nsRefPtr<nsPluginHost> pluginHost = nsPluginHost::GetInst();
 
   if (!pluginHost) {
@@ -2672,6 +2677,13 @@ nsObjectLoadingContent::GetTypeOfContent(const nsCString& aMIMEType)
     return eType_Image;
   }
 
+  // Faking support of the PDF content as a document for EMBED tags
+  // when internal PDF viewer is enabled.
+  if (aMIMEType.LowerCaseEqualsLiteral("application/pdf") &&
+      nsContentUtils::IsPDFJSEnabled()) {
+    return eType_Document;
+  }
+
   // SVGs load as documents, but are their own capability
   bool isSVG = aMIMEType.LowerCaseEqualsLiteral("image/svg+xml");
   Capabilities supportType = isSVG ? eSupportSVG : eSupportDocuments;