Add a NavigationThrottle to the public content/ interface

components/navigation_interception/intercept_navigation_throttle.h

Index: components/navigation_interception/intercept_navigation_throttle.h
diff --git a/components/navigation_interception/intercept_navigation_throttle.h b/components/navigation_interception/intercept_navigation_throttle.h
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index 0000000000000000000000000000000000000000..0b7f74605378266e5e09a549127d53639e1617a4
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+++ b/components/navigation_interception/intercept_navigation_throttle.h
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+// Copyright 2015 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.
+
+#ifndef COMPONENTS_NAVIGATION_INTERCEPTION_INTERCEPT_NAVIGATION_THROTTLE_H_
+#define COMPONENTS_NAVIGATION_INTERCEPTION_INTERCEPT_NAVIGATION_THROTTLE_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/memory/weak_ptr.h"
+#include "content/public/browser/navigation_throttle.h"
+
+class GURL;
+
+namespace content {
+class NavigationHandle;
+class WebContents;
+}
+
+namespace navigation_interception {
+
+class NavigationParams;
+
+// This class allows the provider of the Callback to selectively ignore top
+// level navigations. This is a UI thread class.
+class InterceptNavigationThrottle : public content::NavigationThrottle {
+ public:
+  typedef base::Callback<bool(content::WebContents* /* source */,
+                              const NavigationParams& /* navigation_params */)>
+      CheckCallback;
+
+  InterceptNavigationThrottle(content::NavigationHandle* navigation_handle,
+                              CheckCallback should_ignore_callback);
+  ~InterceptNavigationThrottle() override;
+
+  // content::NavigationThrottle implementation:
+  ThrottleCheckResult WillStartRequest() override;
+  ThrottleCheckResult WillRedirectRequest() override;
+
+ private:
+  ThrottleCheckResult CheckIfShouldIgnoreNavigation(bool is_redirect);
+
+  CheckCallback should_ignore_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterceptNavigationThrottle);
+};
+
+}  // namespace navigation_interception
+
+#endif  // COMPONENTS_NAVIGATION_INTERCEPTION_INTERCEPT_NAVIGATION_THROTTLE_H_