Replace IPC messages in layout_test_render_frame_observer.

content/shell/browser/layout_test/blink_test_controller.h

Index: content/shell/browser/layout_test/blink_test_controller.h
diff --git a/content/shell/browser/layout_test/blink_test_controller.h b/content/shell/browser/layout_test/blink_test_controller.h
index 2d7f699051aebf07dc3e91bfe53b4ac646876e91..45fb8898fff0366d816193332a7c0abb2e753d86 100644
--- a/content/shell/browser/layout_test/blink_test_controller.h
+++ b/content/shell/browser/layout_test/blink_test_controller.h
@@ -26,6 +26,7 @@
 #include "content/public/browser/render_process_host_observer.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/common/web_preferences.h"
+#include "content/shell/common/layout_test.mojom.h"
 #include "content/shell/common/leak_detection_result.h"
 #include "ui/gfx/geometry/size.h"
 
@@ -215,6 +216,8 @@ class BlinkTestController : public base::NonThreadSafe,
   void OnGetBluetoothManualChooserEvents();
   void OnSendBluetoothManualChooserEvent(const std::string& event,
                                          const std::string& argument);
+  mojom::LayoutTestControl* GetLayoutTestControlPtr(RenderFrameHost* frame);
+  void HandleLayoutTestControlError(RenderFrameHost* frame);
 
   std::unique_ptr<BlinkTestResultPrinter> printer_;
 
@@ -278,6 +281,9 @@ class BlinkTestController : public base::NonThreadSafe,
   // renderer created while test is in progress).
   base::DictionaryValue accumulated_layout_test_runtime_flags_changes_;
 
+  // Map from one frame to one mojo pipe.
+  std::map<RenderFrameHost*, mojom::LayoutTestControlAssociatedPtr>
+      layout_test_control_map_;
 #if defined(OS_ANDROID)
   // Because of the nested message pump implementation, Android needs to allow
   // waiting on the UI thread while layout tests are being ran.