Introduce SubframeNavigationFilteringThrottle

components/subresource_filter/content/browser/subframe_filtering_navigation_throttle.h

+// 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.
+
+#ifndef COMPONENTS_SUBRESOURCE_FILTER_CONTENT_BROWSER_SUBFRAME_BLOCKING_NAVIGATION_THROTTLE_H_
+#define COMPONENTS_SUBRESOURCE_FILTER_CONTENT_BROWSER_SUBFRAME_BLOCKING_NAVIGATION_THROTTLE_H_
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "content/public/browser/navigation_throttle.h"
+#include "third_party/WebKit/public/platform/WebDocumentSubresourceFilter.h"
+
+namespace content {
+class NavigationHandle;
+}  // namespace content
+
+namespace subresource_filter {
+
+class AsyncDocumentSubresourceFilter;
+
+// NavigationThrottle responsible for determining the activation level for a
+// given frame (including main frames and subframes). This class should only be
+// created for subframe navigations occuring in document's which are already

[pkalinnikov, 2017/02/14 12:11:07]

nit: s/document's/documents/

[Charlie Harrison, 2017/02/14 14:09:38]

Done.

+// activated and have associated DocumentSubresourceFilters.

[pkalinnikov, 2017/02/14 12:11:07]

Phrasing suggestion:

NavigationThrottle responsible for determining activation levels for direct
subframes of a given |parent| frame (either main frame of a subframe itself),
and cancelling disallowed loads. This class should only be instantiated for
subframe navigations occuring in documents which already have filtering
activated and an associated (Async)DocumentSubresourceFilter.

[Charlie Harrison, 2017/02/14 14:09:38]

Reworded even more, because this class *doesn't* determine activation levels...

+class SubframeFilteringNavigationThrottle : public content::NavigationThrottle {
+ public:
+  SubframeFilteringNavigationThrottle(
+      content::NavigationHandle* handle,
+      AsyncDocumentSubresourceFilter* async_filter);

[pkalinnikov, 2017/02/14 12:11:07]

nit: Please call this consistently with the stored pointer. How about both being
|parent_filter|?

[Charlie Harrison, 2017/02/14 14:09:38]

Done.

+  ~SubframeFilteringNavigationThrottle() override;
+
+  // content::NavigationThrottle:
+  content::NavigationThrottle::ThrottleCheckResult WillStartRequest() override;
+  content::NavigationThrottle::ThrottleCheckResult WillRedirectRequest()
+      override;
+
+ private:
+  content::NavigationThrottle::ThrottleCheckResult DeferToCalculateLoadPolicy();
+  void OnCalculatedLoadPolicy(
+      blink::WebDocumentSubresourceFilter::LoadPolicy policy);
+
+  // Must outlive this class.
+  AsyncDocumentSubresourceFilter* parent_filter_;
+
+  base::WeakPtrFactory<SubframeFilteringNavigationThrottle> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(SubframeFilteringNavigationThrottle);
+};
+
+}  // namespace subresource_filter
+
+#endif  // COMPONENTS_SUBRESOURCE_FILTER_CONTENT_BROWSER_SUBFRAME_BLOCKING_NAVIGATION_THROTTLE_H_