diff -r 000000000000 -r 6474c204b198 docshell/base/nsWebNavigationInfo.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/docshell/base/nsWebNavigationInfo.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,120 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+#include "nsWebNavigationInfo.h"
+#include "nsIWebNavigation.h"
+#include "nsServiceManagerUtils.h"
+#include "nsIDocumentLoaderFactory.h"
+#include "nsIPluginHost.h"
+#include "nsIDocShell.h"
+#include "nsContentUtils.h"
+#include "imgLoader.h"
+
+NS_IMPL_ISUPPORTS(nsWebNavigationInfo, nsIWebNavigationInfo)
+
+#define CONTENT_DLF_CONTRACT "@mozilla.org/content/document-loader-factory;1"
+#define PLUGIN_DLF_CONTRACT \
+    "@mozilla.org/content/plugin/document-loader-factory;1"
+
+nsresult
+nsWebNavigationInfo::Init()
+{
+  nsresult rv;
+  mCategoryManager = do_GetService(NS_CATEGORYMANAGER_CONTRACTID, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsWebNavigationInfo::IsTypeSupported(const nsACString& aType,
+                                     nsIWebNavigation* aWebNav,
+                                     uint32_t* aIsTypeSupported)
+{
+  NS_PRECONDITION(aIsTypeSupported, "null out param?");
+
+  // Note to self: aWebNav could be an nsWebBrowser or an nsDocShell here (or
+  // an nsSHistory, but not much we can do with that).  So if we start using
+  // it here, we need to be careful to get to the docshell correctly.
+  
+  // For now just report what the Gecko-Content-Viewers category has
+  // to say for itself.
+  *aIsTypeSupported = nsIWebNavigationInfo::UNSUPPORTED;
+
+  const nsCString& flatType = PromiseFlatCString(aType);
+  nsresult rv = IsTypeSupportedInternal(flatType, aIsTypeSupported);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (*aIsTypeSupported) {
+    return rv;
+  }
+
+  // If this request is for a docShell that isn't going to allow plugins,
+  // there's no need to try and find a plugin to handle it.
+  nsCOMPtr<nsIDocShell> docShell(do_QueryInterface(aWebNav));
+  bool allowed;
+  if (docShell && NS_SUCCEEDED(docShell->GetAllowPlugins(&allowed)) && !allowed) {
+    return NS_OK;
+  }
+
+  // Try reloading plugins in case they've changed.
+  nsCOMPtr<nsIPluginHost> pluginHost =
+    do_GetService(MOZ_PLUGIN_HOST_CONTRACTID);
+  if (pluginHost) {
+    // false will ensure that currently running plugins will not
+    // be shut down
+    rv = pluginHost->ReloadPlugins();
+    if (NS_SUCCEEDED(rv)) {
+      // OK, we reloaded plugins and there were new ones
+      // (otherwise NS_ERROR_PLUGINS_PLUGINSNOTCHANGED would have
+      // been returned).  Try checking whether we can handle the
+      // content now.
+      return IsTypeSupportedInternal(flatType, aIsTypeSupported);
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult
+nsWebNavigationInfo::IsTypeSupportedInternal(const nsCString& aType,
+                                             uint32_t* aIsSupported)
+{
+  NS_PRECONDITION(aIsSupported, "Null out param?");
+
+
+  nsContentUtils::ContentViewerType vtype = nsContentUtils::TYPE_UNSUPPORTED;
+
+  nsCOMPtr<nsIDocumentLoaderFactory> docLoaderFactory =
+    nsContentUtils::FindInternalContentViewer(aType.get(), &vtype);
+
+  switch (vtype) {
+  case nsContentUtils::TYPE_UNSUPPORTED:
+    *aIsSupported = nsIWebNavigationInfo::UNSUPPORTED;
+    break;
+
+  case nsContentUtils::TYPE_PLUGIN:
+    *aIsSupported = nsIWebNavigationInfo::PLUGIN;
+    break;
+
+  case nsContentUtils::TYPE_UNKNOWN:
+    *aIsSupported = nsIWebNavigationInfo::OTHER;
+    break;
+
+  case nsContentUtils::TYPE_CONTENT:
+    // XXXbz we only need this because images register for the same
+    // contractid as documents, so we can't tell them apart based on
+    // contractid.
+    if (imgLoader::SupportImageWithMimeType(aType.get())) {
+      *aIsSupported = nsIWebNavigationInfo::IMAGE;
+    }
+    else {
+      *aIsSupported = nsIWebNavigationInfo::OTHER;
+    }
+    break;
+  }
+
+  return NS_OK;
+}