Introduce SubframeNavigationFilteringThrottle

components/subresource_filter/content/browser/subframe_filtering_navigation_throttle.cc

+// 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.
+
+#include "components/subresource_filter/content/browser/subframe_filtering_navigation_throttle.h"
+
+#include "base/bind.h"
+#include "components/subresource_filter/content/browser/async_document_subresource_filter.h"
+#include "content/public/browser/navigation_handle.h"
+
+namespace subresource_filter {
+
+SubframeFilteringNavigationThrottle::SubframeFilteringNavigationThrottle(
+    content::NavigationHandle* handle,
+    AsyncDocumentSubresourceFilter* async_filter)

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

nit: Rename to |parent_filter| too (see comment in .h file).

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

Done.

+    : content::NavigationThrottle(handle),
+      parent_filter_(async_filter),
+      weak_ptr_factory_(this) {
+  DCHECK(!handle->IsInMainFrame());
+  DCHECK(parent_filter_);
+}
+
+SubframeFilteringNavigationThrottle::~SubframeFilteringNavigationThrottle() {}
+
+content::NavigationThrottle::ThrottleCheckResult
+SubframeFilteringNavigationThrottle::WillStartRequest() {
+  return DeferToCalculateLoadPolicy();
+}
+
+content::NavigationThrottle::ThrottleCheckResult
+SubframeFilteringNavigationThrottle::WillRedirectRequest() {
+  return DeferToCalculateLoadPolicy();
+}
+
+content::NavigationThrottle::ThrottleCheckResult
+SubframeFilteringNavigationThrottle::DeferToCalculateLoadPolicy() {
+  parent_filter_->GetLoadPolicyForSubdocument(
+      navigation_handle()->GetURL(),
+      base::Bind(&SubframeFilteringNavigationThrottle::OnCalculatedLoadPolicy,
+                 weak_ptr_factory_.GetWeakPtr()));
+  return content::NavigationThrottle::ThrottleCheckResult::DEFER;
+}
+
+void SubframeFilteringNavigationThrottle::OnCalculatedLoadPolicy(
+    blink::WebDocumentSubresourceFilter::LoadPolicy policy) {
+  // TODO(csharrison): Support WouldDisallow pattern and expose the policy for
+  // metrics.
+  if (policy == blink::WebDocumentSubresourceFilter::Disallow) {
+    navigation_handle()->CancelDeferredNavigation(
+        content::NavigationThrottle::CANCEL);

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

We should also to call parent_filter_->ReportDisallowedLoad() here to trigger
the UI.

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

Done.

+  } else {
+    navigation_handle()->Resume();
+  }
+}
+
+}  // namespace subresource_filter