Moved ios popup opening code from Tab to BlockedPopupTabHelper.

ios/web/public/test/web_test_with_web_state.mm

Index: ios/web/public/test/web_test_with_web_state.mm
diff --git a/ios/web/public/test/web_test_with_web_state.mm b/ios/web/public/test/web_test_with_web_state.mm
index c704d647da97c95718c871176a1dd158cac043be..9b09c9e1183b105e55860c0ce93a9e9a2e7609df 100644
--- a/ios/web/public/test/web_test_with_web_state.mm
+++ b/ios/web/public/test/web_test_with_web_state.mm
@@ -39,7 +39,7 @@ void WebTestWithWebState::SetUp() {
 }
 
 void WebTestWithWebState::TearDown() {
-  web_state_.reset();
+  DestroyWebState();
   WebTest::TearDown();
 }
 
@@ -132,6 +132,10 @@ id WebTestWithWebState::ExecuteJavaScript(NSString* script) {
   return [[executionResult retain] autorelease];
 }
 
+void WebTestWithWebState::DestroyWebState() {
+  web_state_.reset();
+}
+
 std::string WebTestWithWebState::BaseUrl() const {
   web::URLVerificationTrustLevel unused_level;
   return web_state()->GetCurrentURL(&unused_level).spec();