Add an experimental permissions API for extensions.

chrome/common/extensions/extension_permission_set.cc

Index: chrome/common/extensions/extension_permission_set.cc
diff --git a/chrome/common/extensions/extension_permission_set.cc b/chrome/common/extensions/extension_permission_set.cc
index 8d27abdff6ed2bbcc1ca6f62572202d073feabb2..9e4534d75a69ec3e6d110fa22630dcd28ad5aa81 100644
--- a/chrome/common/extensions/extension_permission_set.cc
+++ b/chrome/common/extensions/extension_permission_set.cc
@@ -247,6 +247,9 @@ ExtensionPermissionsInfo::ExtensionPermissionsInfo()
   RegisterHostedAppPermission(
       ExtensionAPIPermission::kUnlimitedStorage, "unlimitedStorage", 0,
       ExtensionPermissionMessage::kNone);
+  RegisterHostedAppPermission(
+      ExtensionAPIPermission::kPermissions, "permissions", 0,
+      ExtensionPermissionMessage::kNone);
 
   // Hosted app and private permissions.
   RegisterPermission(
@@ -426,6 +429,56 @@ ExtensionPermissionSet::~ExtensionPermissionSet() {
 }
 
 // static
+ExtensionPermissionSet* ExtensionPermissionSet::CreateDifference(
+    const ExtensionPermissionSet* set1,
+    const ExtensionPermissionSet* set2) {
+  ExtensionPermissionSet empty;
+  const ExtensionPermissionSet* set1_safe = (set1 == NULL) ? &empty : set1;
+  const ExtensionPermissionSet* set2_safe = (set2 == NULL) ? &empty : set2;
+
+  ExtensionAPIPermissionSet apis;
+  std::set_difference(set1_safe->apis().begin(), set1_safe->apis().end(),
+                      set2_safe->apis().begin(), set2_safe->apis().end(),
+                      std::insert_iterator<ExtensionAPIPermissionSet>(
+                          apis, apis.begin()));
+
+  URLPatternSet explicit_hosts;
+  URLPatternSet::CreateDifference(set1_safe->explicit_hosts(),
+                                  set2_safe->explicit_hosts(),
+                                  &explicit_hosts);
+
+  URLPatternSet scriptable_hosts;
+  URLPatternSet::CreateDifference(set1_safe->scriptable_hosts(),
+                                  set2_safe->scriptable_hosts(),
+                                  &scriptable_hosts);
+  return new ExtensionPermissionSet(apis, explicit_hosts, scriptable_hosts);
+}
+
+// static
+ExtensionPermissionSet* ExtensionPermissionSet::CreateIntersection(
+    const ExtensionPermissionSet* set1,
+    const ExtensionPermissionSet* set2) {
+  ExtensionPermissionSet empty;
+  const ExtensionPermissionSet* set1_safe = (set1 == NULL) ? &empty : set1;
+  const ExtensionPermissionSet* set2_safe = (set2 == NULL) ? &empty : set2;
+
+  ExtensionAPIPermissionSet apis;
+  std::set_intersection(set1_safe->apis().begin(), set1_safe->apis().end(),
+                        set2_safe->apis().begin(), set2_safe->apis().end(),
+                        std::insert_iterator<ExtensionAPIPermissionSet>(
+                            apis, apis.begin()));
+  URLPatternSet explicit_hosts;
+  URLPatternSet::CreateIntersection(set1_safe->explicit_hosts(),
+                                    set2_safe->explicit_hosts(),
+                                    &explicit_hosts);
+
+  URLPatternSet scriptable_hosts;
+  URLPatternSet::CreateIntersection(set1_safe->scriptable_hosts(),
+                                    set2_safe->scriptable_hosts(),
+                                    &scriptable_hosts);
+  return new ExtensionPermissionSet(apis, explicit_hosts, scriptable_hosts);
+}
+// static
 ExtensionPermissionSet* ExtensionPermissionSet::CreateUnion(
     const ExtensionPermissionSet* set1,
     const ExtensionPermissionSet* set2) {
@@ -440,10 +493,11 @@ ExtensionPermissionSet* ExtensionPermissionSet::CreateUnion(
                      apis, apis.begin()));
 
   URLPatternSet explicit_hosts;
-  URLPatternSet scriptable_hosts;
   URLPatternSet::CreateUnion(set1_safe->explicit_hosts(),
                              set2_safe->explicit_hosts(),
                              &explicit_hosts);
+
+  URLPatternSet scriptable_hosts;
   URLPatternSet::CreateUnion(set1_safe->scriptable_hosts(),
                              set2_safe->scriptable_hosts(),
                              &scriptable_hosts);
@@ -451,6 +505,31 @@ ExtensionPermissionSet* ExtensionPermissionSet::CreateUnion(
   return new ExtensionPermissionSet(apis, explicit_hosts, scriptable_hosts);
 }
 
+bool ExtensionPermissionSet::operator==(
+    const ExtensionPermissionSet& rhs) const {
+  return apis_ == rhs.apis_ &&
+      scriptable_hosts_ == rhs.scriptable_hosts_ &&
+      explicit_hosts_ == rhs.explicit_hosts_;
+}
+
+bool ExtensionPermissionSet::Contains(const ExtensionPermissionSet& set) const {
+  // Every set includes the empty set.
+  if (set.IsEmpty())
+    return true;
+
+  if (!std::includes(apis_.begin(), apis_.end(),
+                     set.apis().begin(), set.apis().end()))
+    return false;
+
+  if (!explicit_hosts().Contains(set.explicit_hosts()))
+    return false;
+
+  if (!scriptable_hosts().Contains(set.scriptable_hosts()))
+    return false;
+
+  return true;
+}
+
 std::set<std::string> ExtensionPermissionSet::GetAPIsAsStrings() const {
   ExtensionPermissionsInfo* info = ExtensionPermissionsInfo::GetInstance();
   std::set<std::string> apis_str;