Replicate LayoutTestRuntimeFlags across secondary window renderers.

content/shell/renderer/layout_test/layout_test_render_thread_observer.cc

Index: content/shell/renderer/layout_test/layout_test_render_thread_observer.cc
diff --git a/content/shell/renderer/layout_test/layout_test_render_thread_observer.cc b/content/shell/renderer/layout_test/layout_test_render_thread_observer.cc
index 362d98e3dc9d2335ed8c2c5611f49638f4544278..de9c6631586751f6b437f4e9940c596071533152 100644
--- a/content/shell/renderer/layout_test/layout_test_render_thread_observer.cc
+++ b/content/shell/renderer/layout_test/layout_test_render_thread_observer.cc
@@ -7,10 +7,12 @@
 #include "base/command_line.h"
 #include "components/test_runner/test_interfaces.h"
 #include "components/test_runner/web_test_interfaces.h"
+#include "components/test_runner/web_test_runner.h"
 #include "content/common/input/input_event_utils.h"
 #include "content/public/common/content_client.h"
 #include "content/public/renderer/render_thread.h"
 #include "content/public/test/layouttest_support.h"
+#include "content/shell/common/layout_test/layout_test_messages.h"
 #include "content/shell/common/layout_test/layout_test_switches.h"
 #include "content/shell/common/shell_messages.h"
 #include "content/shell/renderer/layout_test/blink_test_runner.h"
@@ -82,6 +84,8 @@ bool LayoutTestRenderThreadObserver::OnControlMessageReceived(
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(LayoutTestRenderThreadObserver, message)
     IPC_MESSAGE_HANDLER(ShellViewMsg_SetWebKitSourceDir, OnSetWebKitSourceDir)
+    IPC_MESSAGE_HANDLER(LayoutTestMsg_ReplicateLayoutTestRuntimeFlagsChanges,
+                        OnReplicateLayoutTestRuntimeFlagsChanges)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
 
@@ -93,4 +97,10 @@ void LayoutTestRenderThreadObserver::OnSetWebKitSourceDir(
   webkit_source_dir_ = webkit_source_dir;
 }
 
+void LayoutTestRenderThreadObserver::OnReplicateLayoutTestRuntimeFlagsChanges(
+    const base::DictionaryValue& changed_layout_test_runtime_flags) {
+  test_interfaces()->TestRunner()->ReplicateLayoutTestRuntimeFlagsChanges(
+      changed_layout_test_runtime_flags);
+}
+
 }  // namespace content