Add unittest to test CWVWebView.

ios/web_view/test/chrome_web_view_kvo_inttest.mm

Index: ios/web_view/test/chrome_web_view_kvo_inttest.mm
diff --git a/ios/web_view/test/chrome_web_view_kvo_inttest.mm b/ios/web_view/test/chrome_web_view_kvo_inttest.mm
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+++ b/ios/web_view/test/chrome_web_view_kvo_inttest.mm
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+// 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 <ChromeWebView/ChromeWebView.h>
+#import <Foundation/Foundation.h>
+
+#import "base/mac/scoped_nsobject.h"
+#import "ios/web_view/test/boolean_observer.h"
+#import "ios/web_view/test/chrome_web_view_test.h"
+#import "ios/web_view/test/web_view_interaction_test_util.h"
+#import "net/base/mac/url_conversions.h"
+#include "testing/gtest_mac.h"
+#include "url/gurl.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+// Tests that the KVO compliant properties of CWVWebView correctly report
+// changes.
+class ChromeWebViewKvoTest : public ios_web_view::ChromeWebViewTest {
+ protected:
+  ChromeWebViewKvoTest() {
+    CWVWebViewConfiguration* configuration =
+        [CWVWebViewConfiguration defaultConfiguration];
+    web_view_.reset([[CWVWebView alloc]
+        initWithFrame:CGRectMake(0.0, 0.0, 100.0, 100.0)
+        configuration:configuration]);
+  }
+
+  // Web View used to listen for expected KVO property changes.
+  base::scoped_nsobject<CWVWebView> web_view_;
+};
+
+namespace ios_web_view {
+
+// Tests that CWVWebView correctly reports |canGoBack| and |canGoForward| state.
+TEST_F(ChromeWebViewKvoTest, CanGoBackForward) {
+  BooleanObserver* back_observer = [[BooleanObserver alloc] init];
+  [back_observer setObservedObject:web_view_ keyPath:@"canGoBack"];
+
+  BooleanObserver* forward_observer = [[BooleanObserver alloc] init];
+  [forward_observer setObservedObject:web_view_ keyPath:@"canGoForward"];
+
+  ASSERT_FALSE(back_observer.lastValue);
+  ASSERT_FALSE(forward_observer.lastValue);
+
+  // Define pages in reverse order so the links can reference the "next" page.
+  GURL page_3_url = GetUrlForPageWithTitle("Page 3");
+
+  std::string page_2_html =
+      "<a id='link_2' href='" + page_3_url.spec() + "'>Link 2</a>";
+  GURL page_2_url = GetUrlForPageWithHTMLBody(page_2_html);
+
+  std::string page_1_html =
+      "<a id='link_1' href='" + page_2_url.spec() + "'>Link 1</a>";
+  GURL page_1_url = GetUrlForPageWithHTMLBody(page_1_html);
+
+  LoadUrl(web_view_, net::NSURLWithGURL(page_1_url));
+  // Loading initial URL should not affect back/forward navigation state.
+  EXPECT_FALSE([back_observer.lastValue boolValue]);
+  EXPECT_FALSE([forward_observer.lastValue boolValue]);
+
+  // Navigate to page 2.
+  EXPECT_TRUE(test::TapChromeWebViewElementWithId(web_view_, @"link_1"));
+  WaitForPageLoadCompletion(web_view_);
+  EXPECT_TRUE([back_observer.lastValue boolValue]);
+  EXPECT_FALSE([forward_observer.lastValue boolValue]);
+
+  // Navigate back to page 1.
+  [web_view_ goBack];
+  WaitForPageLoadCompletion(web_view_);
+  EXPECT_FALSE([back_observer.lastValue boolValue]);
+  EXPECT_TRUE([forward_observer.lastValue boolValue]);
+
+  // Navigate forward to page 2.
+  [web_view_ goForward];
+  WaitForPageLoadCompletion(web_view_);
+  EXPECT_TRUE([back_observer.lastValue boolValue]);
+  EXPECT_FALSE([forward_observer.lastValue boolValue]);
+
+  // Navigate to page 3.
+  EXPECT_TRUE(test::TapChromeWebViewElementWithId(web_view_, @"link_2"));
+  WaitForPageLoadCompletion(web_view_);
+  EXPECT_TRUE([back_observer.lastValue boolValue]);
+  EXPECT_FALSE([forward_observer.lastValue boolValue]);
+
+  // Navigate back to page 2.
+  [web_view_ goBack];
+  WaitForPageLoadCompletion(web_view_);
+  EXPECT_TRUE([back_observer.lastValue boolValue]);
+  EXPECT_TRUE([forward_observer.lastValue boolValue]);
+}
+
+}  // namespace ios_web_view