Disarm LockToOrigin for extensions under --isolate-extensions.

chrome/browser/extensions/chrome_content_browser_client_extensions_part.cc

Index: chrome/browser/extensions/chrome_content_browser_client_extensions_part.cc
diff --git a/chrome/browser/extensions/chrome_content_browser_client_extensions_part.cc b/chrome/browser/extensions/chrome_content_browser_client_extensions_part.cc
index 684fbf44ced6e98dce59a7c0b67d434314cf93f4..db7849125222ffadba3999969ce720f5e71ec6a6 100644
--- a/chrome/browser/extensions/chrome_content_browser_client_extensions_part.cc
+++ b/chrome/browser/extensions/chrome_content_browser_client_extensions_part.cc
@@ -218,6 +218,14 @@ bool ChromeContentBrowserClientExtensionsPart::ShouldLockToOrigin(
             .GetExtensionOrAppByURL(effective_site_url);
     if (extension && extension->is_hosted_app())
       return false;
+
+    // http://crbug.com/600441 workaround: Extension process reuse, implemented
+    // in ShouldTryToUseExistingProcessHost(), means that extension processes
+    // aren't always actually dedicated to a single origin, even in
+    // --isolate-extensions. TODO(nick): Fix this.
+    if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
+            ::switches::kSitePerProcess))
+      return false;
   }
   return true;
 }