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
new file mode 100644
index 0000000000000000000000000000000000000000..23e53759846b5dfc1ea8702fb430f53939a62dde
--- /dev/null
+++ b/components/navigation_interception/intercept_navigation_throttle.h
@@ -0,0 +1,53 @@
+// 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.
+class InterceptNavigationThrottle : public content::NavigationThrottle {
+ public:
+  typedef base::Callback<bool(content::WebContents* /* source */,
+                              const NavigationParams& /* navigation_params */)>

[carlosk, 2015/08/28 16:40:24]

For a future change we should consider replacing this to directly accept the
NavigationHandle instead of doing the conversion to NavigationParams. Maybe add
a TODO?

[clamy, 2015/09/03 15:30:51]

Nope because they get converted to an equivalent java struct. So the C++ struct
will have to be initialized anyway.

+      CheckCallback;
+
+  InterceptNavigationThrottle(content::NavigationHandle* navigation_handle,
+                              content::WebContents* web_contents,

[nasko, 2015/08/31 23:25:15]

I'd put web_contents as the first parameter, as it is the scope in which
navigation_handle exists.

[clamy, 2015/09/03 15:30:51]

Done.

+                              CheckCallback should_ignore_callback);
+  ~InterceptNavigationThrottle() override;
+
+  // content::NavigationThrottle implementation:
+  ThrottleCheckResult WillStartRequest() override;
+  ThrottleCheckResult WillRedirectRequest() override;
+
+ private:
+  ThrottleCheckResult CheckIfShouldIgnoreNavigation(bool is_redirect);
+
+  content::WebContents* web_contents_;
+  CheckCallback should_ignore_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterceptNavigationThrottle);
+};
+
+}  // namespace navigation_interception
+
+#endif  // COMPONENTS_NAVIGATION_INTERCEPTION_INTERCEPT_NAVIGATION_THROTTLE_H_