Separate RenderViewHost from RenderWidgetHost, part 4: delegate

chrome/browser/extensions/api/processes/processes_api.cc

 // Copyright (c) 2012 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 "chrome/browser/extensions/api/processes/processes_api.h"
 
 #include "base/callback.h"
 #include "base/json/json_writer.h"
 #include "base/lazy_instance.h"
 #include "base/location.h"
@@ skipping 101 matching lines @@
     return tabs_list;
 
   int tab_id = -1;
   // We need to loop through all the RVHs to ensure we collect the set of all
   // tabs using this renderer process.
   scoped_ptr<content::RenderWidgetHostIterator> widgets(
       content::RenderWidgetHost::GetRenderWidgetHosts());
   while (content::RenderWidgetHost* widget = widgets->GetNextHost()) {
     if (widget->GetProcess()->GetID() != process_id)
       continue;
-    if (!widget->IsRenderView())

[sky, 2015/10/26 21:07:38]

How come this is safe? If widget is not a RenderViewHost would 123 be null, and
127 then crash?

[Avi (use Gerrit), 2015/10/26 23:20:14]

If widget isn't a RVH then the RenderViewHost* |host| on line 123 will be null.
Passing in a null RVH to WebContents::FromRenderViewHost now is safe and _also_
returns null (new in this CL!) and that null result will be tested on line 126.

[sky, 2015/10/27 13:12:33]

Ok, I missed that. I looked at the existing code which doesn't handle null.

-      continue;
 
     content::RenderViewHost* host = content::RenderViewHost::From(widget);
     content::WebContents* contents =
         content::WebContents::FromRenderViewHost(host);
     if (contents) {
       tab_id = ExtensionTabUtil::GetTabId(contents);
       if (tab_id != -1)
         tabs_list->Append(new base::FundamentalValue(tab_id));
     }
   }
@@ skipping 638 matching lines @@
 
   SetResult(processes);
   SendResponse(true);
 
   // Balance the AddRef in the RunAsync.
   Release();
 #endif  // defined(ENABLE_TASK_MANAGER)
 }
 
 }  // namespace extensions