Introduce AsyncDocumentSubresourceFilter.

components/subresource_filter/content/browser/async_document_subresource_filter.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/async_document_subresource_filter.h"
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/callback.h"
+#include "base/location.h"
+#include "base/task_runner_util.h"
+#include "components/subresource_filter/core/common/memory_mapped_ruleset.h"
+
+namespace subresource_filter {
+
+using InitializationParams =
+    AsyncDocumentSubresourceFilter::InitializationParams;
+
+InitializationParams::InitializationParams() = default;
+InitializationParams::~InitializationParams() = default;
+InitializationParams::InitializationParams(InitializationParams&&) = default;
+InitializationParams& InitializationParams::operator=(InitializationParams&&) =
+    default;
+
+AsyncDocumentSubresourceFilter::AsyncDocumentSubresourceFilter(
+    VerifiedRuleset::Handle* ruleset_handle,
+    InitializationParams params,
+    base::Callback<void(ActivationState)> activation_state_callback)
+    : task_runner_(ruleset_handle->task_runner()),
+      core_(new Core(), base::OnTaskRunnerDeleter(task_runner_)) {
+  // Note: It is safe to post |ruleset_handle|'s VerifiedRuleset pointer,
+  // because a task to delete it can only be posted to (and, therefore,
+  // processed by) |task_runner| after this method returns, hence after the
+  // below task is posted.
+  base::PostTaskAndReplyWithResult(
+      task_runner_, FROM_HERE,
+      base::Bind(&Core::Initialize, base::Unretained(core_.get()),
+                 base::Passed(&params), ruleset_handle->ruleset_.get()),
+      std::move(activation_state_callback));
+}
+
+AsyncDocumentSubresourceFilter::~AsyncDocumentSubresourceFilter() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+}
+
+void AsyncDocumentSubresourceFilter::GetLoadPolicyForSubdocument(
+    const GURL& subdocument_url,
+    LoadPolicyCallback result_callback) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  auto compute_load_policy = [](AsyncDocumentSubresourceFilter::Core* core,
+                                const GURL& subdocument_url) {
+    DCHECK(core);
+    DocumentSubresourceFilter* filter = core->filter();
+    return filter ? filter->GetLoadPolicyForSubdocument(subdocument_url)
+                  : LoadPolicy::Allow;
+  };
+
+  // TODO(pkalinnikov): Think about avoiding copy of |subdocument_url| if it is
+  // too big and won't be allowed anyway (e.g., it's a data: URI).
+  base::PostTaskAndReplyWithResult(
+      task_runner_, FROM_HERE,
+      base::Bind(compute_load_policy, core_.get(), subdocument_url),
+      std::move(result_callback));
+}
+
+AsyncDocumentSubresourceFilter::Core::Core() {
+  thread_checker_.DetachFromThread();
+}
+
+AsyncDocumentSubresourceFilter::Core::~Core() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+}
+
+ActivationState AsyncDocumentSubresourceFilter::Core::Initialize(
+    InitializationParams params,
+    VerifiedRuleset* verified_ruleset) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(verified_ruleset);
+
+  const MemoryMappedRuleset* ruleset = verified_ruleset->Get();
+  if (!ruleset)
+    return ActivationState(ActivationLevel::DISABLED);
+
+  ActivationState activation_state =
+      ComputeActivationState(params.document_url, params.parent_document_origin,
+                             params.parent_activation_state, ruleset);
+
+  filter_.emplace(url::Origin(params.document_url), activation_state, ruleset,
+                  std::move(params.first_disallowed_load_callback));
+
+  return activation_state;
+}
+
+}  // namespace subresource_filter