Convert utility process extension Unpacker IPC to mojo

extensions/browser/extensions_test.cc

Index: extensions/browser/extensions_test.cc
diff --git a/extensions/browser/extensions_test.cc b/extensions/browser/extensions_test.cc
index 4d1ccf3053bf23ff5fa415545e8e859c45bd9e89..f9f88a107396febf551987a681d23aa9ca11ae91 100644
--- a/extensions/browser/extensions_test.cc
+++ b/extensions/browser/extensions_test.cc
@@ -9,6 +9,7 @@
 #include "content/public/common/content_client.h"
 #include "content/public/test/test_browser_context.h"
 #include "extensions/browser/test_extensions_browser_client.h"
+#include "extensions/test/test_content_browser_client.h"
 #include "extensions/test/test_content_utility_client.h"
 
 namespace extensions {
@@ -22,10 +23,12 @@ namespace extensions {
 //   }
 // };
 ExtensionsTest::ExtensionsTest()
-    : content_utility_client_(new TestContentUtilityClient),
+    : content_browser_client_(new TestContentBrowserClient),
+      content_utility_client_(new TestContentUtilityClient),
       browser_context_(new content::TestBrowserContext),
       extensions_browser_client_(
           new TestExtensionsBrowserClient(browser_context_.get())) {
+  content::SetBrowserClientForTesting(content_browser_client_.get());
   content::SetUtilityClientForTesting(content_utility_client_.get());
   ExtensionsBrowserClient::Set(extensions_browser_client_.get());
   extensions_browser_client_->set_extension_system_factory(