Don't abort the PDF stream if a navigation is intiated within the same page.

extensions/browser/guest_view/mime_handler_view/mime_handler_stream_manager.cc

 // Copyright 2015 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 "extensions/browser/guest_view/mime_handler_view/mime_handler_stream_manager.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/memory/singleton.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
@@ skipping 205 matching lines @@
   if (initial_load_for_frame_ && content::IsBrowserSideNavigationEnabled()) {
     initial_load_for_frame_ = false;
     return;
   }
   AbortStream();
 }
 
 void MimeHandlerStreamManager::EmbedderObserver::DidStartNavigation(
     content::NavigationHandle* navigation_handle) {
   // If the top level frame is navigating away, clean up the stream.
-  if (navigation_handle->IsInMainFrame())
+  if (navigation_handle->IsInMainFrame() && !navigation_handle->IsSamePage())
     AbortStream();
 }
 
 void MimeHandlerStreamManager::EmbedderObserver::RenderFrameHostChanged(
     content::RenderFrameHost* old_host,
     content::RenderFrameHost* new_host) {
   // If the old_host is null, then it means that a subframe is being created.
   // Don't treat this like a host change.
   if (!old_host)
     return;
@@ skipping 40 matching lines @@
   if (frame_tree_node_id_ != -1) {
     return render_frame_host->GetFrameTreeNodeId() == frame_tree_node_id_;
   } else {
     DCHECK((render_frame_id_ != -1) && (render_process_id_ != -1));
     return render_frame_host->GetRoutingID() == render_frame_id_ &&
            render_frame_host->GetProcess()->GetID() == render_process_id_;
   }
 }
 
 }  // namespace extensions