[ios] Convert BlockedPopupHandler into a tab helper class.

ios/chrome/browser/web/blocked_popup_tab_helper_unittest.mm

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "ios/chrome/browser/web/blocked_popup_tab_helper.h"
+
+#include "base/memory/ptr_util.h"
+#include "components/infobars/core/infobar.h"
+#include "components/infobars/core/infobar_manager.h"
+#include "ios/chrome/browser/infobars/infobar_manager_impl.h"
+#import "ios/web/public/test/fakes/test_navigation_manager.h"
+#import "ios/web/public/test/fakes/test_web_state.h"
+#include "ios/web/web_state/blocked_popup_info.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/platform_test.h"
+#include "url/gurl.h"
+
+// Test fixture for BlockedPopupTabHelper class.
+class BlockedPopupTabHelperTest : public PlatformTest {
+ protected:
+  BlockedPopupTabHelperTest() : web_state_(new web::TestWebState()) {
+    web_state_->SetNavigationManager(
+        base::MakeUnique<web::TestNavigationManager>());
+
+    BlockedPopupTabHelper::CreateForWebState(web_state_.get());
+    InfoBarManagerImpl::CreateForWebState(web_state_.get());
+  }
+
+ protected:
+  // Expose ivars for testing.
+  bool IsObservingSources() {
+    BlockedPopupTabHelper* helper =
+        BlockedPopupTabHelper::FromWebState(web_state_.get());
+    return helper->scoped_observer_.IsObservingSources();
+  }
+
+  std::unique_ptr<web::TestWebState> web_state_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(BlockedPopupTabHelperTest);
+};
+
+// Tests that an infobar is added to the infobar manager when
+// BlockedPopupTabHelper::HandlePopup() is called.
+TEST_F(BlockedPopupTabHelperTest, ShowAndDismissInfoBar) {
+  const GURL test_url("https://popups.example.com");
+  web::BlockedPopupInfo popup_info(test_url, web::Referrer(), nil, nil);
+
+  // Check that there are no infobars showing and no registered observers.
+  infobars::InfoBarManager* infobar_manager =
+      InfoBarManagerImpl::FromWebState(web_state_.get());
+  EXPECT_EQ(0U, infobar_manager->infobar_count());
+  EXPECT_FALSE(IsObservingSources());
+
+  // Call |HandlePopup| to show an infobar.
+  BlockedPopupTabHelper* tab_helper =
+      BlockedPopupTabHelper::FromWebState(web_state_.get());
+  tab_helper->HandlePopup(popup_info);
+  ASSERT_EQ(1U, infobar_manager->infobar_count());
+  EXPECT_TRUE(IsObservingSources());

[Eugene But (OOO till 7-30), 2017/01/23 16:37:47]

From Google Testing Guidelines: "Test code using real APIs - don’t define back
doors only for tests."
https://goto.google.com/unit-test-practices?cl=head#public-apis

For this specific test, it does not look like it is important to know that
InfobarManager is being observed by BlockedPopupTabHelper.

[rohitrao (ping after 24h), 2017/01/24 13:16:03]

Noted.  Leaving this in for now, but will followup via email with you and
baxley.

+
+  // Dismiss the infobar and check that the tab helper no longer has any
+  // registered observers.
+  infobar_manager->infobar_at(0)->RemoveSelf();
+  EXPECT_EQ(0U, infobar_manager->infobar_count());
+  EXPECT_FALSE(IsObservingSources());
+}