Add unit test and supporting code to test process overflow case.

chrome/browser/renderer_host/site_instance.cc

 // Copyright (c) 2006-2008 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/renderer_host/site_instance.h"
 
 #include "chrome/browser/browsing_instance.h"
 #include "chrome/browser/dom_ui/dom_ui_factory.h"
 #include "chrome/browser/extensions/extensions_service.h"
 #include "chrome/browser/renderer_host/browser_render_process_host.h"
@@ skipping 30 matching lines @@
   // (within the same BrowsingInstance) can safely create a new SiteInstance.
   if (has_site_)
     browsing_instance_->UnregisterSiteInstance(this);
 }
 
 bool SiteInstance::HasProcess() const {
   return (process_ != NULL);
 }
 
 RenderProcessHost* SiteInstance::GetProcess() {
+  // TODO(erikkay) It would be nice to ensure that the renderer type had been
+  // properly set before we get here.  The default tab creation case winds up
+  // with no site set at this point, so it will default to TYPE_NORMAL.  This
+  // may not be correct, so we'll wind up potentially creating a process that
+  // we then throw away, or worse sharing a process with the wrong process type.
+  // See crbug.com/43448.
+
   // Create a new process if ours went away or was reused.
   if (!process_) {
     // See if we should reuse an old process
     if (RenderProcessHost::ShouldTryToUseExistingProcessHost())
       process_ = RenderProcessHost::GetExistingProcessHost(
           browsing_instance_->profile(), GetRendererType());
 
     // Otherwise (or if that fails), create a new one.
     if (!process_) {
       if (render_process_host_factory_) {
@@ skipping 126 matching lines @@
       profile->GetExtensionsService()->GetExtensionByWebExtent(url);
   if (extension) {
     // If the URL is part of an extension's web extent, convert it to an
     // extension URL.
     return extension->GetResourceURL(url.path());
   } else {
     return url;
   }
 }
 
+/*static*/
+RenderProcessHost::Type SiteInstance::RendererTypeForURL(const GURL& url) {
+  if (!url.is_valid())
+    return RenderProcessHost::TYPE_NORMAL;
+
+  if (url.SchemeIs(chrome::kExtensionScheme))
+    return RenderProcessHost::TYPE_EXTENSION;
+
+  // TODO(erikkay) creis recommends using UseDOMUIForURL instead.
+  if (DOMUIFactory::HasDOMUIScheme(url))
+    return RenderProcessHost::TYPE_DOMUI;
+
+  return RenderProcessHost::TYPE_NORMAL;
+}
+
 RenderProcessHost::Type SiteInstance::GetRendererType() {
   // We may not have a site at this point, which generally means this is a
   // normal navigation.
-  if (!has_site_ || !site_.is_valid())
+  if (!has_site_)
     return RenderProcessHost::TYPE_NORMAL;
 
-  if (site_.SchemeIs(chrome::kExtensionScheme))
-    return RenderProcessHost::TYPE_EXTENSION;
-
-  if (DOMUIFactory::HasDOMUIScheme(site_))
-    return RenderProcessHost::TYPE_DOMUI;
-
-  return RenderProcessHost::TYPE_NORMAL;
+  return RendererTypeForURL(site_);
 }
 
 void SiteInstance::Observe(NotificationType type,
                            const NotificationSource& source,
                            const NotificationDetails& details) {
   DCHECK(type == NotificationType::RENDERER_PROCESS_TERMINATED);
   RenderProcessHost* rph = Source<RenderProcessHost>(source).ptr();
   if (rph == process_)
     process_ = NULL;
 }