Added a PolicyDomainDescriptor.

chrome/browser/policy/policy_domain_descriptor.cc

Index: chrome/browser/policy/policy_domain_descriptor.cc
diff --git a/chrome/browser/policy/policy_domain_descriptor.cc b/chrome/browser/policy/policy_domain_descriptor.cc
new file mode 100644
index 0000000000000000000000000000000000000000..cadc2d616fe857e8be4ac0936f6096423ea04743
--- /dev/null
+++ b/chrome/browser/policy/policy_domain_descriptor.cc
@@ -0,0 +1,99 @@
+// Copyright (c) 2013 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 "chrome/browser/policy/policy_domain_descriptor.h"
+
+#include "base/stl_util.h"
+#include "chrome/browser/policy/policy_bundle.h"
+#include "chrome/browser/policy/policy_map.h"
+#include "chrome/browser/policy/policy_schema.h"
+
+namespace policy {
+
+namespace {
+
+bool Matches(const PolicySchema* schema, const base::Value& value) {

[bartfab (slow), 2013/05/21 12:10:56]

#include "base/values.h"

[Joao da Silva, 2013/05/21 17:50:14]

Done.

+  if (!schema) {
+    // Schema not found, invalid entry.
+    return false;
+  }
+
+  if (!value.IsType(schema->type()))
+    return false;
+
+  const base::DictionaryValue* dict = NULL;
+  const base::ListValue* list = NULL;
+  if (value.GetAsDictionary(&dict)) {
+    for (base::DictionaryValue::Iterator it(*dict); !it.IsAtEnd();
+         it.Advance()) {
+      if (!Matches(schema->GetSchemaForProperty(it.key()), it.value()))
+        return false;
+    }
+  } else if (value.GetAsList(&list)) {
+    for (base::ListValue::const_iterator it = list->begin();
+         it != list->end(); ++it) {
+      if (!*it || !Matches(schema->GetSchemaForItems(), **it))
+        return false;
+    }
+  }
+
+  return true;
+}
+
+}  // namespace
+
+PolicyDomainDescriptor::PolicyDomainDescriptor(PolicyDomain domain)
+    : domain_(domain) {}
+
+void PolicyDomainDescriptor::SetComponent(const std::string& component_id,
+                                          scoped_ptr<PolicySchema> schema) {
+  const PolicySchema*& previous = schema_map_[component_id];
+  delete previous;
+  previous = schema.release();

[bartfab (slow), 2013/05/21 12:10:56]

Could you rename |previous| to something like |entry| or |component_schema|
maybe? "previous = ..." looks like you are modifying the previous schema instead
of replacing it with the new schema.

[Joao da Silva, 2013/05/21 17:50:14]

Done.

+}
+
+void PolicyDomainDescriptor::FilterBundle(PolicyBundle* bundle) const {
+  // Chrome policies are not filtered, so that typos appear in about:policy.
+  DCHECK_NE(POLICY_DOMAIN_CHROME, domain_);

[bartfab (slow), 2013/05/21 12:10:56]

#include "base/logging.h"

[Joao da Silva, 2013/05/21 17:50:14]

Done.

+
+  for (PolicyBundle::const_iterator it_bundle = bundle->begin();
+       it_bundle != bundle->end(); ++it_bundle) {
+    const PolicyNamespace& ns = it_bundle->first;
+    if (ns.domain != domain_)
+      continue;
+
+    SchemaMap::const_iterator it_schema = schema_map_.find(ns.component_id);
+    if (it_schema == schema_map_.end()) {
+      // Component ID not found.
+      bundle->Get(ns).Clear();

[bartfab (slow), 2013/05/21 12:10:56]

Why not make |it_bundle| a non-const iterator, allowing you to
it_bundle.second->Clear()

[Joao da Silva, 2013/05/21 17:50:14]

PolicyBundle only has const_iterators, but there's no reason why it couldn't
have iterators too. Done.

+      continue;
+    }
+
+    // TODO(joaodasilva): if a component is registered but doesn't have a schema
+    // then its policies aren't filtered. This behavior is enabled for M29 to
+    // allow a graceful update of the Legacy Browser Support extension; it'll
+    // be removed for M30. http://crbug.com/240704
+    if (!it_schema->second)
+      continue;
+
+    const PolicySchema* component_schema = it_schema->second;
+    PolicyMap& map = bundle->Get(ns);

[bartfab (slow), 2013/05/21 12:10:56]

As above, if |it_bundle| were non-const, you could use it_bundle.second here.

[Joao da Silva, 2013/05/21 17:50:14]

Done.

+    PolicyMap::const_iterator it_map = map.begin();

[bartfab (slow), 2013/05/21 12:10:56]

for and while are equivalent of course. In terms of readability, I think a for
loop would be clearer here:

for (PolicyMap::const_iterator it_map = map.begin();
     it_map != map.end(); ) {

[Joao da Silva, 2013/05/21 17:50:14]

Done.

+    while (it_map != map.end()) {
+      const std::string& policy_name = it_map->first;
+      const base::Value* policy_value = it_map->second.value;
+      const PolicySchema* policy_schema =
+          component_schema->GetSchemaForProperty(policy_name);
+      ++it_map;

[bartfab (slow), 2013/05/21 12:10:56]

Alternatively (and using the STL more efficiently):

if (!policy_value || !Matches(policy_schema, *policy_value))
  it_map = map.Erase(policy_name);
else
  ++it_map;

[Joao da Silva, 2013/05/21 17:50:14]

PolicyMap is not an std::map: it doesn't have iterators (const_iterators can be
used to mutate a map), and its Erase() method doesn't return an iterator. I'll
leave this as is.

+      if (!policy_value || !Matches(policy_schema, *policy_value))
+        map.Erase(policy_name);
+    }
+  }
+}
+
+PolicyDomainDescriptor::~PolicyDomainDescriptor() {
+  STLDeleteValues(&schema_map_);
+}
+
+}  // namespace policy