Add support for a "split" incognito behavior for extensions.

chrome/browser/extensions/extension_apitest.cc

Index: chrome/browser/extensions/extension_apitest.cc
diff --git a/chrome/browser/extensions/extension_apitest.cc b/chrome/browser/extensions/extension_apitest.cc
index ba4da598086e0b7dfc6c2566f1d6f150ec13ce50..c5e1f54b8b8c266127bf2128fd76de806c7433c9 100644
--- a/chrome/browser/extensions/extension_apitest.cc
+++ b/chrome/browser/extensions/extension_apitest.cc
@@ -11,7 +11,8 @@
 #include "chrome/common/notification_registrar.h"
 #include "chrome/test/ui_test_utils.h"
 
-ExtensionApiTest::ResultCatcher::ResultCatcher() {
+ExtensionApiTest::ResultCatcher::ResultCatcher()
+    : profile_restriction_(NULL) {
   registrar_.Add(this, NotificationType::EXTENSION_TEST_PASSED,
                  NotificationService::AllSources());
   registrar_.Add(this, NotificationType::EXTENSION_TEST_FAILED,
@@ -44,6 +45,11 @@ bool ExtensionApiTest::ResultCatcher::GetNextResult() {
 void ExtensionApiTest::ResultCatcher::Observe(
     NotificationType type, const NotificationSource& source,
     const NotificationDetails& details) {
+  if (profile_restriction_ &&
+      Source<Profile>(source).ptr() != profile_restriction_) {
+    return;
+  }
+
   switch (type.value) {
     case NotificationType::EXTENSION_TEST_PASSED:
       std::cout << "Got EXTENSION_TEST_PASSED notification.\n";