Cleanup ios_web_view integration tests.

ios/web_view/test/chrome_web_view_test.h

Index: ios/web_view/test/chrome_web_view_test.h
diff --git a/ios/web_view/test/chrome_web_view_test.h b/ios/web_view/test/chrome_web_view_test.h
index 389338a469e416657322995ee7a3de019d56651e..92505c53d3d835de0b7513eacc86a051130bb928 100644
--- a/ios/web_view/test/chrome_web_view_test.h
+++ b/ios/web_view/test/chrome_web_view_test.h
@@ -8,6 +8,7 @@
 #include <memory>
 #include <string>
 
+#import "base/mac/scoped_nsobject.h"
 #include "testing/platform_test.h"
 
 namespace net {
@@ -51,6 +52,10 @@ class ChromeWebViewTest : public PlatformTest {
   // PlatformTest methods.
   void SetUp() override;
 
+  // CWVWebView created with default configuration and frame equal to screen
+  // bounds.
+  base::scoped_nsobject<CWVWebView> web_view_;
+
   // Embedded server for handling requests sent to the URLs returned by the
   // GetURL* methods.
   std::unique_ptr<net::test_server::EmbeddedTestServer> test_server_;