Switch to using .debug_frame for CFI.

This will make it easier to strip or compress CFI using standard tools.

It also saves some space since we do not need .eh_frame_hdr anymore.

Bug:20556771
Change-Id: I8656b1ff248e4b12cb94924800c3a91fac8bdda4
diff --git a/compiler/elf_writer_quick.cc b/compiler/elf_writer_quick.cc
index 96dd7ca..af42364 100644
--- a/compiler/elf_writer_quick.cc
+++ b/compiler/elf_writer_quick.cc
@@ -43,7 +43,8 @@
 // it is used by C++ exception handling (which we do not use so we
 // can choose either).  C++ compilers generally tend to use .eh_frame
 // because if they need it sometimes, they might as well always use it.
-constexpr dwarf::CFIFormat kCFIFormat = dwarf::DW_EH_FRAME_FORMAT;
+// Let's use .debug_frame because it is easier to strip or compress.
+constexpr dwarf::CFIFormat kCFIFormat = dwarf::DW_DEBUG_FRAME_FORMAT;
 
 template <typename ElfTypes>
 bool ElfWriterQuick<ElfTypes>::Create(File* elf_file,