Introduce SubframeNavigationFilteringThrottle

components/subresource_filter/content/browser/subframe_filtering_navigation_throttle.h

Index: components/subresource_filter/content/browser/subframe_filtering_navigation_throttle.h
diff --git a/components/subresource_filter/content/browser/subframe_filtering_navigation_throttle.h b/components/subresource_filter/content/browser/subframe_filtering_navigation_throttle.h
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index 0000000000000000000000000000000000000000..3b594b9d8b3955d97b1976c3d93f80dec5382f40
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+++ b/components/subresource_filter/content/browser/subframe_filtering_navigation_throttle.h
@@ -0,0 +1,52 @@
+// 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 filtering direct subframe navigations

[engedy, 2017/02/14 22:04:33]

Comment wording ideas:

NavigationThrottle responsible for filtering subframe document loads, which are
considered subresource loads of their parent frame, hence are subject to
subresource filtering using the parent frame's AsyncDocumentSubresourceFilter. 

The throttle should only be instantiated for navigations occuring in subframes
owned by documents which already have filtering activated, and therefore an
associated (Async)DocumentSubresourceFilter.

[Charlie Harrison, 2017/02/14 23:06:55]

Nice, done

+// associated with activated frames. It should only be instantiated for
+// subframe navigations occuring in documents which already have filtering
+// activated and an associated (Async)DocumentSubresourceFilter.
+class SubframeFilteringNavigationThrottle : public content::NavigationThrottle {

[engedy, 2017/02/14 22:04:33]

This name is somewhat ambiguous, what do you think about:

SubframeNavigationFilteringThrottle, or
SubframeDocumentFilteringThrottle?

[Charlie Harrison, 2017/02/14 23:06:55]

I prefer SubframeNavigationFilteringThrottle, changed it.

+ public:
+  SubframeFilteringNavigationThrottle(
+      content::NavigationHandle* handle,
+      AsyncDocumentSubresourceFilter* parent_filter);

[engedy, 2017/02/14 22:04:33]

nit: How about calling this more specifically parent_frame_filter?

[Charlie Harrison, 2017/02/14 23:06:55]

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_