[Extensions] Start making chrome://extensions use extensions APIs

Allow chrome://extensions to use the developerPrivate and
management apis, and make it do so for enabling/disabling
extensions.
Also, shave yaks:
- Make management api check requirements for extensions.
- Make feature provider aware of complex parents.
And bonus:
- Remove WeakPtr interface from RequirementsChecker

BUG=461039

Review URL: https://codereview.chromium.org/951633002

Cr-Commit-Position: refs/heads/master@{#317871}

1 files changed, 14 insertions, 1 deletions

diff --git a/extensions/common/features/base_feature_provider.cc b/extensions/common/features/base_feature_provider.cc
index 9b927cc..40807f41 100644
--- a/extensions/common/features/base_feature_provider.cc
+++ b/extensions/common/features/base_feature_provider.cc
@@ -66,7 +66,20 @@ BaseFeatureProvider::BaseFeatureProvider(const base::DictionaryValue& root,
         split.pop_back();
         if (root.HasKey(parent_name)) {
           const base::DictionaryValue* parent = nullptr;
-          CHECK(root.GetDictionaryWithoutPathExpansion(parent_name, &parent));
+          if (!root.GetDictionaryWithoutPathExpansion(parent_name, &parent)) {
+            // If the parent is a complex feature, find the parent with the
+            // 'default_parent' flag.
+            const base::ListValue* parent_list = nullptr;
+            CHECK(root.GetListWithoutPathExpansion(parent_name, &parent_list));
+            for (size_t i = 0; i < parent_list->GetSize(); ++i) {
+              CHECK(parent_list->GetDictionary(i, &parent));
+              if (parent->HasKey("default_parent"))
+                break;
+              parent = nullptr;
+            }
+            CHECK(parent) << parent_name << " must declare one of its features"
+                << " the default parent, with {\"default_parent\": true}.";
+          }
           parse_stack.push(std::make_pair(parent_name, parent));
           bool no_parent = false;
           parent->GetBoolean("noparent", &no_parent);