New WebContents created via ctrl-click should be in a new process.

content/browser/frame_host/render_frame_host_impl.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/frame_host/render_frame_host_impl.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 1152 matching lines @@
     // on the frame's unique name.  If this can't be found, fall back to the
     // default params using RequestOpenURL below.
     if (frame_tree_node_->navigator()->NavigateNewChildFrame(this,
                                                              validated_url))
       return;
   }
 
   TRACE_EVENT1("navigation", "RenderFrameHostImpl::OpenURL", "url",
                validated_url.possibly_invalid_spec());
 
+  // When |params.disposition| asks OpenURL to create new contents, it always
+  // happens because of an explicit user request for new content creation (i.e.
+  // opening a link using ctrl-click or middle click).  In such cases, the new
+  // content should be created in a new renderer to break opener relationship
+  // (see https://crbug.com/658386) and to conserve memory per renderer (see
+  // https://crbug.com/23815).  Note that new content creation that wasn't
+  // explicitly requested by the user (i.e. left-clicking a link with
+  // target=_blank) goes through a different code path (through
+  // WebViewClient::CreateView).
+  bool kForceNewProcessForNewContents = true;
+
   frame_tree_node_->navigator()->RequestOpenURL(
       this, validated_url, params.uses_post, params.resource_request_body,
       params.extra_headers, params.referrer, params.disposition,
-      params.should_replace_current_entry, params.user_gesture);
+      kForceNewProcessForNewContents, params.should_replace_current_entry,
+      params.user_gesture);
 }
 
 void RenderFrameHostImpl::OnCancelInitialHistoryLoad() {
   // A Javascript navigation interrupted the initial history load.  Check if an
   // initial subframe cross-process navigation needs to be canceled as a result.
   // TODO(creis, clamy): Cancel any cross-process navigation in PlzNavigate.
   if (GetParent() && !frame_tree_node_->has_committed_real_load() &&
       frame_tree_node_->render_manager()->pending_frame_host()) {
     frame_tree_node_->render_manager()->CancelPendingIfNecessary(
         frame_tree_node_->render_manager()->pending_frame_host());
@@ skipping 2477 matching lines @@
 }
 
 void RenderFrameHostImpl::ForwardGetInterfaceToRenderFrame(
     const std::string& interface_name,
     mojo::ScopedMessagePipeHandle pipe) {
   GetRemoteInterfaces()->GetInterface(interface_name, std::move(pipe));
 }
 #endif
 
 }  // namespace content