Add IsDynamicPartition API to easily check if a partition is dynamic

Test: treehugger
Change-Id: I655e4d6114a25c58857679985cd5e08581c0faab
diff --git a/aosp/dynamic_partition_control_android.cc b/aosp/dynamic_partition_control_android.cc
index 7ccc39a..ca12b3d 100644
--- a/aosp/dynamic_partition_control_android.cc
+++ b/aosp/dynamic_partition_control_android.cc
@@ -1283,4 +1283,14 @@
   return snapshot_->MapAllSnapshots(kMapSnapshotTimeout);
 }
 
+bool DynamicPartitionControlAndroid::IsDynamicPartition(
+    const std::string& partition_name) {
+  if (dynamic_partition_list_.empty() &&
+      GetDynamicPartitionsFeatureFlag().IsEnabled()) {
+    CHECK(ListDynamicPartitionsForSlot(source_slot_, &dynamic_partition_list_));
+  }
+  return std::find(dynamic_partition_list_.begin(),
+                   dynamic_partition_list_.end(),
+                   partition_name) != dynamic_partition_list_.end();
+}
 }  // namespace chromeos_update_engine
diff --git a/aosp/dynamic_partition_control_android.h b/aosp/dynamic_partition_control_android.h
index a2a42cc..4a2b114 100644
--- a/aosp/dynamic_partition_control_android.h
+++ b/aosp/dynamic_partition_control_android.h
@@ -95,6 +95,8 @@
 
   bool UnmapAllPartitions() override;
 
+  bool IsDynamicPartition(const std::string& part_name) override;
+
  protected:
   // These functions are exposed for testing.
 
@@ -303,6 +305,7 @@
   bool is_target_dynamic_ = false;
   uint32_t source_slot_ = UINT32_MAX;
   uint32_t target_slot_ = UINT32_MAX;
+  std::vector<std::string> dynamic_partition_list_;
 
   DISALLOW_COPY_AND_ASSIGN(DynamicPartitionControlAndroid);
 };
diff --git a/aosp/mock_dynamic_partition_control_android.h b/aosp/mock_dynamic_partition_control_android.h
index d281803..8d8ddb3 100644
--- a/aosp/mock_dynamic_partition_control_android.h
+++ b/aosp/mock_dynamic_partition_control_android.h
@@ -99,6 +99,7 @@
               (override));
   MOCK_METHOD(bool, MapAllPartitions, (), (override));
   MOCK_METHOD(bool, UnmapAllPartitions, (), (override));
+  MOCK_METHOD(bool, IsDynamicPartition, (const std::string&), (override));
 
   void set_fake_mapped_devices(const std::set<std::string>& fake) override {
     DynamicPartitionControlAndroid::set_fake_mapped_devices(fake);