[DRAFT] Create RenderFrameHostManager.

content/browser/loader/cross_site_resource_handler.cc

Index: content/browser/loader/cross_site_resource_handler.cc
diff --git a/content/browser/loader/cross_site_resource_handler.cc b/content/browser/loader/cross_site_resource_handler.cc
index f6274bd0ca344c1338b6013ace48674f566ac140..e9bea980ad1e4dafd95a7780d53130d8a662b959 100644
--- a/content/browser/loader/cross_site_resource_handler.cc
+++ b/content/browser/loader/cross_site_resource_handler.cc
@@ -7,6 +7,7 @@
 #include <string>
 
 #include "base/bind.h"
+#include "base/command_line.h"
 #include "base/logging.h"
 #include "content/browser/cross_site_request_manager.h"
 #include "content/browser/loader/resource_dispatcher_host_impl.h"
@@ -17,7 +18,9 @@
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/global_request_id.h"
 #include "content/public/browser/resource_controller.h"
+#include "content/public/common/content_switches.h"
 #include "content/public/common/resource_response.h"
+#include "content/public/common/url_constants.h"
 #include "net/http/http_response_headers.h"
 #include "net/url_request/url_request.h"
 
@@ -91,6 +94,26 @@ bool CrossSiteResourceHandler::OnResponseStarted(
   bool should_transfer =
       GetContentClient()->browser()->ShouldSwapProcessesForRedirect(
           info->GetContext(), request()->original_url(), request()->url());
+
+  // When the --site-per-process flag is passed, we transfer processes for
+  // cross-site subframe navigations.
+  // TODO(creis): Skip this for chrome: pages for now, since they host cross
+  // site iframes and don't have referrers.
+  // TODO(creis): This doesn't work for hosted apps, due to passing NULL to
+  // IsSameWebSite.  It should be possible to always send the navigation to the
+  // UI thread to make a policy decision, which could let us eliminate the
+  // renderer-side check in RenderViewImpl::decidePolicyForNavigation as well.
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kSitePerProcess)) {
+    GURL referrer(request()->referrer());
+    if (info->GetResourceType() == ResourceType::SUB_FRAME &&
+        !request()->url().SchemeIs(chrome::kChromeUIScheme) &&
+        !SiteInstance::IsSameWebSite(NULL, request()->url(), referrer)) {
+      LOG(INFO) << "CSRH: Transferring for a cross-process subframe: " <<
+          request()->url();
+      should_transfer = true;
+    }
+  }
+
   bool swap_needed = should_transfer ||
       CrossSiteRequestManager::GetInstance()->
           HasPendingCrossSiteRequest(info->GetChildID(), info->GetRouteID());