[ios] Added API to enable/disable web usage for WebState.

ios/web/public/test/test_web_state.mm

 // Copyright 2014 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.
 
 #include "ios/web/public/test/test_web_state.h"
 
 #include <stdint.h>
 
 #include "base/callback.h"
 
 namespace web {
 
 TestWebState::TestWebState()
-    : trust_level_(kAbsolute), content_is_html_(true) {}
+    : web_usage_enabled_(false),
+      trust_level_(kAbsolute),
+      content_is_html_(true) {}
 
 TestWebState::~TestWebState() = default;
 
-UIView* TestWebState::GetView() {
-  return nullptr;
-}
-
 WebStateDelegate* TestWebState::GetDelegate() {
   return nil;
 }
 
 void TestWebState::SetDelegate(WebStateDelegate* delegate) {}
 
 BrowserState* TestWebState::GetBrowserState() const {
   return nullptr;
 }
 
+bool TestWebState::IsWebUsageEnabled() const {
+  return web_usage_enabled_;
+}
+
+void TestWebState::SetWebUsageEnabled(bool enabled) {
+  web_usage_enabled_ = enabled;
+}
+
+UIView* TestWebState::GetView() {
+  return nullptr;
+}
+
 NavigationManager* TestWebState::GetNavigationManager() {
   return nullptr;
 }
 
 CRWJSInjectionReceiver* TestWebState::GetJSInjectionReceiver() const {
   return nullptr;
 }
 
 void TestWebState::ExecuteJavaScript(const base::string16& javascript) {}
 
@@ skipping 74 matching lines @@
                                 const ImageDownloadCallback& callback) {
   return 0;
 }
 
 base::WeakPtr<WebState> TestWebState::AsWeakPtr() {
   NOTREACHED();
   return base::WeakPtr<WebState>();
 }
 
 }  // namespace web