[Extensions] Make methods return refptrs for PermissionSet

PermissionSet is refcounted (why is another issue), but multiple functions are
returning raw pointers to constructed PermissionSets, which makes for ugly casts
and potential leaks. Make all functions return refptrs.

Review URL: https://codereview.chromium.org/1353543002

Cr-Commit-Position: refs/heads/master@{#349497}

3 files changed, 39 insertions, 51 deletions

diff --git a/extensions/common/permissions/permission_set.cc b/extensions/common/permissions/permission_set.cc
index 4687102..5cd8d05 100644
--- a/extensions/common/permissions/permission_set.cc
+++ b/extensions/common/permissions/permission_set.cc
@@ -44,77 +44,65 @@ PermissionSet::PermissionSet(
 }
 
 // static
-PermissionSet* PermissionSet::CreateDifference(
-    const PermissionSet* set1,
-    const PermissionSet* set2) {
-  scoped_refptr<PermissionSet> empty = new PermissionSet();
-  const PermissionSet* set1_safe = (set1 == NULL) ? empty.get() : set1;
-  const PermissionSet* set2_safe = (set2 == NULL) ? empty.get() : set2;
-
+scoped_refptr<const PermissionSet> PermissionSet::CreateDifference(
+    const PermissionSet& set1,
+    const PermissionSet& set2) {
   APIPermissionSet apis;
-  APIPermissionSet::Difference(set1_safe->apis(), set2_safe->apis(), &apis);
+  APIPermissionSet::Difference(set1.apis(), set2.apis(), &apis);
 
   ManifestPermissionSet manifest_permissions;
-  ManifestPermissionSet::Difference(set1_safe->manifest_permissions(),
-                                    set2_safe->manifest_permissions(),
+  ManifestPermissionSet::Difference(set1.manifest_permissions(),
+                                    set2.manifest_permissions(),
                                     &manifest_permissions);
 
   URLPatternSet explicit_hosts = URLPatternSet::CreateDifference(
-      set1_safe->explicit_hosts(), set2_safe->explicit_hosts());
+      set1.explicit_hosts(), set2.explicit_hosts());
 
   URLPatternSet scriptable_hosts = URLPatternSet::CreateDifference(
-      set1_safe->scriptable_hosts(), set2_safe->scriptable_hosts());
+      set1.scriptable_hosts(), set2.scriptable_hosts());
 
-  return new PermissionSet(apis, manifest_permissions,
-                           explicit_hosts, scriptable_hosts);
+  return make_scoped_refptr(new PermissionSet(
+      apis, manifest_permissions, explicit_hosts, scriptable_hosts));
 }
 
 // static
-PermissionSet* PermissionSet::CreateIntersection(
-    const PermissionSet* set1,
-    const PermissionSet* set2) {
-  scoped_refptr<PermissionSet> empty = new PermissionSet();
-  const PermissionSet* set1_safe = (set1 == NULL) ? empty.get() : set1;
-  const PermissionSet* set2_safe = (set2 == NULL) ? empty.get() : set2;
-
+scoped_refptr<const PermissionSet> PermissionSet::CreateIntersection(
+    const PermissionSet& set1,
+    const PermissionSet& set2) {
   APIPermissionSet apis;
-  APIPermissionSet::Intersection(set1_safe->apis(), set2_safe->apis(), &apis);
+  APIPermissionSet::Intersection(set1.apis(), set2.apis(), &apis);
 
   ManifestPermissionSet manifest_permissions;
-  ManifestPermissionSet::Intersection(set1_safe->manifest_permissions(),
-                                      set2_safe->manifest_permissions(),
+  ManifestPermissionSet::Intersection(set1.manifest_permissions(),
+                                      set2.manifest_permissions(),
                                       &manifest_permissions);
 
   URLPatternSet explicit_hosts = URLPatternSet::CreateSemanticIntersection(
-      set1_safe->explicit_hosts(), set2_safe->explicit_hosts());
+      set1.explicit_hosts(), set2.explicit_hosts());
   URLPatternSet scriptable_hosts = URLPatternSet::CreateSemanticIntersection(
-      set1_safe->scriptable_hosts(), set2_safe->scriptable_hosts());
+      set1.scriptable_hosts(), set2.scriptable_hosts());
 
   return new PermissionSet(apis, manifest_permissions,
                            explicit_hosts, scriptable_hosts);
 }
 
 // static
-PermissionSet* PermissionSet::CreateUnion(
-    const PermissionSet* set1,
-    const PermissionSet* set2) {
-  scoped_refptr<PermissionSet> empty = new PermissionSet();
-  const PermissionSet* set1_safe = (set1 == NULL) ? empty.get() : set1;
-  const PermissionSet* set2_safe = (set2 == NULL) ? empty.get() : set2;
-
+scoped_refptr<const PermissionSet> PermissionSet::CreateUnion(
+    const PermissionSet& set1,
+    const PermissionSet& set2) {
   APIPermissionSet apis;
-  APIPermissionSet::Union(set1_safe->apis(), set2_safe->apis(), &apis);
+  APIPermissionSet::Union(set1.apis(), set2.apis(), &apis);
 
   ManifestPermissionSet manifest_permissions;
-  ManifestPermissionSet::Union(set1_safe->manifest_permissions(),
-                               set2_safe->manifest_permissions(),
+  ManifestPermissionSet::Union(set1.manifest_permissions(),
+                               set2.manifest_permissions(),
                                &manifest_permissions);
 
-  URLPatternSet explicit_hosts = URLPatternSet::CreateUnion(
-      set1_safe->explicit_hosts(), set2_safe->explicit_hosts());
+  URLPatternSet explicit_hosts =
+      URLPatternSet::CreateUnion(set1.explicit_hosts(), set2.explicit_hosts());
 
   URLPatternSet scriptable_hosts = URLPatternSet::CreateUnion(
-      set1_safe->scriptable_hosts(), set2_safe->scriptable_hosts());
+      set1.scriptable_hosts(), set2.scriptable_hosts());
 
   return new PermissionSet(apis, manifest_permissions,
                            explicit_hosts, scriptable_hosts);
diff --git a/extensions/common/permissions/permission_set.h b/extensions/common/permissions/permission_set.h
index e7b5311..a6c62be 100644
--- a/extensions/common/permissions/permission_set.h
+++ b/extensions/common/permissions/permission_set.h
@@ -40,20 +40,21 @@ class PermissionSet
                 const URLPatternSet& explicit_hosts,
                 const URLPatternSet& scriptable_hosts);
 
-  // Creates a new permission set equal to |set1| - |set2|, passing ownership of
-  // the new set to the caller.
-  static PermissionSet* CreateDifference(
-      const PermissionSet* set1, const PermissionSet* set2);
+  // Creates a new permission set equal to |set1| - |set2|.
+  static scoped_refptr<const PermissionSet> CreateDifference(
+      const PermissionSet& set1,
+      const PermissionSet& set2);
 
   // Creates a new permission set equal to the intersection of |set1| and
-  // |set2|, passing ownership of the new set to the caller.
-  static PermissionSet* CreateIntersection(
-      const PermissionSet* set1, const PermissionSet* set2);
+  // |set2|.
+  static scoped_refptr<const PermissionSet> CreateIntersection(
+      const PermissionSet& set1,
+      const PermissionSet& set2);
 
   // Creates a new permission set equal to the union of |set1| and |set2|.
-  // Passes ownership of the new set to the caller.
-  static PermissionSet* CreateUnion(
-      const PermissionSet* set1, const PermissionSet* set2);
+  static scoped_refptr<const PermissionSet> CreateUnion(
+      const PermissionSet& set1,
+      const PermissionSet& set2);
 
   bool operator==(const PermissionSet& rhs) const;
   bool operator!=(const PermissionSet& rhs) const;
diff --git a/extensions/common/permissions/permissions_data.cc b/extensions/common/permissions/permissions_data.cc
index ad45cd5..7fdbd2c 100644
--- a/extensions/common/permissions/permissions_data.cc
+++ b/extensions/common/permissions/permissions_data.cc
@@ -138,8 +138,7 @@ void PermissionsData::UpdateTabSpecificPermissions(
   if (iter == tab_specific_permissions_.end())
     tab_specific_permissions_[tab_id] = permissions;
   else
-    iter->second =
-        PermissionSet::CreateUnion(iter->second.get(), permissions.get());
+    iter->second = PermissionSet::CreateUnion(*(iter->second), *permissions);
 }
 
 void PermissionsData::ClearTabSpecificPermissions(int tab_id) const {