Explicitly initialize secondary renderers for layout tests.

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 5974f337c82483a72bda7248225704c0999b8ce8..362d98e3dc9d2335ed8c2c5611f49638f4544278 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
@@ -5,20 +5,17 @@
 #include "content/shell/renderer/layout_test/layout_test_render_thread_observer.h"
 
 #include "base/command_line.h"
-#include "components/test_runner/event_sender.h"
 #include "components/test_runner/test_interfaces.h"
 #include "components/test_runner/web_test_interfaces.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/renderer/render_view.h"
 #include "content/public/test/layouttest_support.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"
 #include "third_party/WebKit/public/web/WebKit.h"
 #include "third_party/WebKit/public/web/WebRuntimeFeatures.h"
-#include "third_party/WebKit/public/web/WebView.h"
 #include "v8/include/v8.h"
 
 using blink::WebFrame;
@@ -37,8 +34,7 @@ LayoutTestRenderThreadObserver::GetInstance() {
 }
 
 LayoutTestRenderThreadObserver::LayoutTestRenderThreadObserver()
-    : main_test_runner_(NULL),
-      test_delegate_(NULL) {
+    : test_delegate_(nullptr) {
   CHECK(!g_instance);
   g_instance = this;
   RenderThread::Get()->AddObserver(this);
@@ -77,12 +73,6 @@ void LayoutTestRenderThreadObserver::SetTestDelegate(
   test_delegate_ = delegate;
 }
 
-void LayoutTestRenderThreadObserver::SetMainWindow(RenderView* view) {
-  BlinkTestRunner* test_runner = BlinkTestRunner::Get(view);
-  test_interfaces_->SetWebView(view->GetWebView(), test_runner->proxy());
-  main_test_runner_ = test_runner;
-}
-
 void LayoutTestRenderThreadObserver::OnRenderProcessShutdown() {
   test_interfaces_.reset();
 }