Factor DocumentSubresourceFilter out of SubresourceFilterAgent.

components/subresource_filter/content/renderer/document_subresource_filter.h

Index: components/subresource_filter/content/renderer/document_subresource_filter.h
diff --git a/components/subresource_filter/content/renderer/document_subresource_filter.h b/components/subresource_filter/content/renderer/document_subresource_filter.h
new file mode 100644
index 0000000000000000000000000000000000000000..c7c1d4ec49d86afb4c4e921739eb0070cfb94994
--- /dev/null
+++ b/components/subresource_filter/content/renderer/document_subresource_filter.h
@@ -0,0 +1,72 @@
+// Copyright 2016 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_RENDERER_DOCUMENT_SUBRESOURCE_FILTER_H_
+#define COMPONENTS_SUBRESOURCE_FILTER_CONTENT_RENDERER_DOCUMENT_SUBRESOURCE_FILTER_H_
+
+#include <stddef.h>
+
+#include <vector>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "components/subresource_filter/core/common/activation_state.h"
+#include "third_party/WebKit/public/platform/WebDocumentSubresourceFilter.h"
+
+class GURL;
+
+namespace subresource_filter {
+
+class MemoryMappedRuleset;
+
+// Performs filtering of subresource loads in the scope of a given document.
+//
+// TODO(engedy): This is a placeholder implementation that treats the entire
+// ruleset as the UTF-8 representation of a string, and will disallow
+// subresource loads from URL paths having this string as a suffix if it is
+// non-empty. This enables exercising the feature end-to-end in a browsertest.
+// Replace this with the actual filtering logic.
+class DocumentSubresourceFilter : public blink::WebDocumentSubresourceFilter {
+ public:
+  // Constructs a new filter that will:
+  //  -- Operate at the prescribed |activation_state|, which must be either
+  //     ActivationState::DRYRUN or ActivationState::ENABLED. In the former
+  //     case filtering will be performed but no loads will be disallowed.
+  //  -- Hold a reference to and use |ruleset| for its entire lifetime.
+  //  -- Expect |ancestor_document_urls| to be the URLs of documents loaded into
+  //     nested frames, starting with the current frame and ending with the main
+  //     frame. This provides the context for evaluating domain-specific rules.
+  DocumentSubresourceFilter(
+      ActivationState activation_state,
+      const scoped_refptr<const MemoryMappedRuleset>& ruleset,
+      std::vector<GURL> ancestor_document_urls);
+  ~DocumentSubresourceFilter() override;
+
+  // blink::WebDocumentSubresourceFilter:
+  bool allowLoad(const blink::WebURL& resourceUrl,
+                 blink::WebURLRequest::RequestContext) override;
+
+  // Statistics on the number of subresource loads that were evaluated, were
+  // matched by filtering rules, and were disallowed, respectively, during the
+  // lifetime of |this| filter.
+  size_t num_loads_evaluated() const { return num_loads_evaluated_; }
+  size_t num_loads_matching_rules() const { return num_loads_matching_rules_; }
+  size_t num_loads_disallowed() const { return num_loads_disallowed_; }
+
+ private:
+  bool DoesLoadMatchFilteringRules(const GURL& resource_url);
+
+  ActivationState activation_state_;
+  scoped_refptr<const MemoryMappedRuleset> ruleset_;
+
+  size_t num_loads_evaluated_ = 0;
+  size_t num_loads_matching_rules_ = 0;
+  size_t num_loads_disallowed_ = 0;
+
+  DISALLOW_COPY_AND_ASSIGN(DocumentSubresourceFilter);
+};
+
+}  // namespace subresource_filter
+
+#endif  // COMPONENTS_SUBRESOURCE_FILTER_CONTENT_RENDERER_DOCUMENT_SUBRESOURCE_FILTER_H_