Navigation transitions: Place transition page in same process as destination page.

content/browser/renderer_host/render_process_host_impl.cc

Index: content/browser/renderer_host/render_process_host_impl.cc
diff --git a/content/browser/renderer_host/render_process_host_impl.cc b/content/browser/renderer_host/render_process_host_impl.cc
index 528401214dca53a59305782fae8e9122f260aa13..40ca0dd3ea81e991a9d8a69ea534a76bdbca6a08 100644
--- a/content/browser/renderer_host/render_process_host_impl.cc
+++ b/content/browser/renderer_host/render_process_host_impl.cc
@@ -103,6 +103,7 @@
 #include "content/browser/storage_partition_impl.h"
 #include "content/browser/streams/stream_context.h"
 #include "content/browser/tracing/trace_message_filter.h"
+#include "content/browser/transition_request_manager.h"
 #include "content/browser/vibration/vibration_message_filter.h"
 #include "content/browser/webui/web_ui_controller_factory_registry.h"
 #include "content/browser/worker_host/worker_message_filter.h"
@@ -1781,6 +1782,11 @@ bool RenderProcessHost::ShouldTryToUseExistingProcessHost(
   if (run_renderer_in_process())
     return true;
 
+  // If this is a transition, we want to use GetExistingProcessHost to find
+  // the appropriate renderer process to use.
+  if (url.SchemeIs(kNavigationTransitionScheme))
+    return true;
+
   // NOTE: Sometimes it's necessary to create more render processes than
   //       GetMaxRendererProcessCount(), for instance when we want to create
   //       a renderer process for a browser context that has no existing
@@ -1812,6 +1818,24 @@ RenderProcessHost* RenderProcessHost::GetExistingProcessHost(
     iter.Advance();
   }
 
+  int preferred_process_id =
+      TransitionRequestManager::GetInstance()->
+          GetPendingTransitionProcessIDByToken(site_url);
+
+  if (preferred_process_id != ChildProcessHost::kInvalidUniqueID) {
+    for (std::vector<RenderProcessHost*>::iterator it =
+        suitable_renderers.begin(); it != suitable_renderers.end(); ++it) {
+      RenderProcessHost* current_host = *it;
+      if (current_host->GetID() == preferred_process_id) {
+        if (RenderProcessHostImpl::IsSuitableHost(current_host,
+                                                  browser_context,
+                                                  site_url))
+          return current_host;
+        break;
+      }
+    }
+  }
+
   // Now pick a random suitable renderer, if we have any.
   if (!suitable_renderers.empty()) {
     int suitable_count = static_cast<int>(suitable_renderers.size());