From 6557402e1086a0295709c9372f2fadd1fb001901 Mon Sep 17 00:00:00 2001
From: Paul Bone <pbone@mozilla.com>
Date: Thu, 16 Jan 2020 03:52:46 +0000
Subject: [PATCH] Bug 1597154 - pt 3. Defer to documentchannel for process
 switching for all schemes r=mattwoodrow

Differential Revision: https://phabricator.services.mozilla.com/D58899

--HG--
extra : moz-landing-system : lando
---
 docshell/base/nsDocShell.cpp  |  2 ++
 toolkit/modules/E10SUtils.jsm | 51 +++++++++++++++++++++++++----------
 2 files changed, 39 insertions(+), 14 deletions(-)

diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index c25f2637ffd4..f9ec5054f7c8 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -9374,6 +9374,8 @@ static bool IsConsideredSameOriginForUIR(nsIPrincipal* aTriggeringPrincipal,
   return NS_OK;
 }
 
+// Changes here should also be made in
+// E10SUtils.documentChannelPermittedForURI().
 static bool SchemeUsesDocChannel(nsIURI* aURI) {
   if (SchemeIsJavascript(aURI) || NS_IsAboutBlank(aURI)) {
     return false;
diff --git a/toolkit/modules/E10SUtils.jsm b/toolkit/modules/E10SUtils.jsm
index 3a2c7bb8f87b..1f557df25321 100644
--- a/toolkit/modules/E10SUtils.jsm
+++ b/toolkit/modules/E10SUtils.jsm
@@ -137,7 +137,22 @@ const kSafeSchemes = [
   "xmpp",
 ];
 
-const kDocumentChannelAllowedSchemes = ["http", "https", "ftp", "data"];
+const kDocumentChannelDeniedSchemes = ["javascript"];
+const kDocumentChannelDeniedURIs = [
+  "about:blank",
+  "about:printpreview",
+  "about:privatebrowsing",
+  "about:crashcontent",
+];
+
+// Changes here should also be made in SchemeUsesDocChannel in
+// nsDocShell.cpp.
+function documentChannelPermittedForURI(aURI) {
+  return (
+    !kDocumentChannelDeniedSchemes.includes(aURI.scheme) &&
+    !kDocumentChannelDeniedURIs.includes(aURI.spec)
+  );
+}
 
 // Note that even if the scheme fits the criteria for a web-handled scheme
 // (ie it is compatible with the checks registerProtocolHandler uses), it may
@@ -724,9 +739,10 @@ var E10SUtils = {
     // for now, and let DocumentChannel do it during the response.
     if (
       currentRemoteType != NOT_REMOTE &&
+      requiredRemoteType != NOT_REMOTE &&
       uriObject &&
       (remoteSubframes || documentChannel) &&
-      kDocumentChannelAllowedSchemes.includes(uriObject.scheme)
+      documentChannelPermittedForURI(uriObject)
     ) {
       mustChangeProcess = false;
     }
@@ -788,18 +804,6 @@ var E10SUtils = {
       return false;
     }
 
-    // If we are using DocumentChannel or remote subframes (fission), and
-    // are loading a HTTP URI, we can start the load in the current
-    // process, and then perform the switch later-on using the
-    // RedirectProcessChooser mechanism.
-    if (
-      Services.appinfo.remoteType != NOT_REMOTE &&
-      (useRemoteSubframes || documentChannel) &&
-      kDocumentChannelAllowedSchemes.includes(aURI.scheme)
-    ) {
-      return true;
-    }
-
     // If we are in a Large-Allocation process, and it wouldn't be content visible
     // to change processes, we want to load into a new process so that we can throw
     // this one out. We don't want to move into a new process if we have post data,
@@ -841,6 +845,25 @@ var E10SUtils = {
       );
     }
 
+    // If we are using DocumentChannel or remote subframes (fission), we
+    // can start the load in the current process, and then perform the
+    // switch later-on using the nsIProcessSwitchRequestor mechanism.
+    let wantRemoteType = this.getRemoteTypeForURIObject(
+      aURI,
+      true,
+      useRemoteSubframes,
+      Services.appinfo.remoteType,
+      webNav.currentURI
+    );
+    if (
+      (useRemoteSubframes || documentChannel) &&
+      Services.appinfo.remoteType != NOT_REMOTE &&
+      wantRemoteType != NOT_REMOTE &&
+      documentChannelPermittedForURI(aURI)
+    ) {
+      return true;
+    }
+
     // If the URI can be loaded in the current process then continue
     return this.shouldLoadURIInThisProcess(aURI, useRemoteSubframes);
   },