ART: Change InstructionSetFeatures to return unique_ptr

This makes clear the ownership of the object.

Test: m test-art-host
Change-Id: I55fa734f04bc3046d370f4dcf98ce6b17c59e234
diff --git a/oatdump/oatdump.cc b/oatdump/oatdump.cc
index 4e81d50..da0db01 100644
--- a/oatdump/oatdump.cc
+++ b/oatdump/oatdump.cc
@@ -115,13 +115,13 @@
 
   bool Symbolize() {
     const InstructionSet isa = oat_file_->GetOatHeader().GetInstructionSet();
-    const InstructionSetFeatures* features = InstructionSetFeatures::FromBitmap(
+    std::unique_ptr<const InstructionSetFeatures> features = InstructionSetFeatures::FromBitmap(
         isa, oat_file_->GetOatHeader().GetInstructionSetFeaturesBitmap());
 
     File* elf_file = OS::CreateEmptyFile(output_name_.c_str());
     std::unique_ptr<BufferedOutputStream> output_stream(
         MakeUnique<BufferedOutputStream>(MakeUnique<FileOutputStream>(elf_file)));
-    builder_.reset(new ElfBuilder<ElfTypes>(isa, features, output_stream.get()));
+    builder_.reset(new ElfBuilder<ElfTypes>(isa, features.get(), output_stream.get()));
 
     builder_->Start();