This defers starting background extension page RenderViews

chrome/browser/ui/startup/startup_browser_creator_impl.cc

Index: chrome/browser/ui/startup/startup_browser_creator_impl.cc
diff --git a/chrome/browser/ui/startup/startup_browser_creator_impl.cc b/chrome/browser/ui/startup/startup_browser_creator_impl.cc
index 3a7b5c32a9b8dcf15459b57acab0c990bc7198e0..1e65793d0b3d40bab4a9bbff860d1963200b9a33 100644
--- a/chrome/browser/ui/startup/startup_browser_creator_impl.cc
+++ b/chrome/browser/ui/startup/startup_browser_creator_impl.cc
@@ -32,6 +32,7 @@
 #include "chrome/browser/defaults.h"
 #include "chrome/browser/extensions/extension_creator.h"
 #include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/extensions/pack_extension_job.h"
 #include "chrome/browser/first_run/first_run.h"
 #include "chrome/browser/google/google_util.h"
@@ -389,6 +390,12 @@ bool StartupBrowserCreatorImpl::Launch(Profile* profile,
     ShellIntegration::MigrateChromiumShortcuts();
 #endif  // defined(OS_WIN)
 
+  // If we deferred creation of background extension hosts, we want to create
+  // them now that the session (if any) has been restored.
+  ExtensionProcessManager* process_manager =
+      extensions::ExtensionSystem::Get(profile)->process_manager();

[sky, 2013/09/04 21:55:34]

Will this force creation of any extension bits that might not have been running?

[Greg Spencer (Chromium), 2013/09/04 22:17:35]

It shouldn't on systems where extensions are enabled: the profile manager will
have already been initialized by this point (which is what initializes the
ExtensionSystem by calling InitForRegularProfile currently), so the Get() won't
create anything new, and the process_manager() call just returns a member of
ExtensionService that should already have been created when the ExtensionService
was.

Your comment made me realize that I probably needed to surround this new piece
with "#if defined(EXTENSIONS_ENABLED)", however, so I did that.

[Greg Spencer (Chromium), 2013/09/04 22:20:25]

Err, I mean ENABLE_EXTENSIONS (which is what I really put in the code).

+  process_manager->DeferBackgroundHostCreation(false);
+
   return true;
 }