Add --stable-release-mode to content_shell

content/shell/renderer/shell_render_process_observer.cc

Index: content/shell/renderer/shell_render_process_observer.cc
diff --git a/content/shell/renderer/shell_render_process_observer.cc b/content/shell/renderer/shell_render_process_observer.cc
index 6c445fa8030867b3bb04bba102521fe94b92a0a8..2694993e8c7c1fb47110e1f1c1ac23fa9612b61b 100644
--- a/content/shell/renderer/shell_render_process_observer.cc
+++ b/content/shell/renderer/shell_render_process_observer.cc
@@ -15,10 +15,12 @@
 #include "content/shell/renderer/shell_content_renderer_client.h"
 #include "content/shell/renderer/webkit_test_runner.h"
 #include "third_party/WebKit/public/testing/WebTestInterfaces.h"
+#include "third_party/WebKit/public/web/WebRuntimeFeatures.h"
 #include "third_party/WebKit/public/web/WebView.h"
 #include "webkit/glue/webkit_glue.h"
 
 using WebKit::WebFrame;
+using WebKit::WebRuntimeFeatures;
 using WebTestRunner::WebTestDelegate;
 using WebTestRunner::WebTestInterfaces;
 
@@ -68,6 +70,11 @@ void ShellRenderProcessObserver::WebKitInitialized() {
   webkit_glue::SetJavaScriptFlags(" --expose-gc");
   RenderThread::Get()->RegisterExtension(extensions_v8::GCExtension::Get());
 
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(
+    switches::kStableReleaseMode)) {
+    WebRuntimeFeatures::enableTestOnlyFeatures(true);
+  }
+
   test_interfaces_.reset(new WebTestInterfaces);
   test_interfaces_->resetAll();
 }