Pull the implementation of the code metrics out of the inline cost

analysis implementation. The header was already separated. Also cleanup
all the comments in the header to follow a nice modern doxygen form.

There is still plenty of cruft here, but some of that will fall out in
subsequent refactorings and this was an easy step in the right
direction. No functionality changed here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152898 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/CMakeLists.txt

@@ -10,6 +10,7 @@ add_llvm_library(LLVMAnalysis
   BranchProbabilityInfo.cpp
   CFGPrinter.cpp
   CaptureTracking.cpp
+  CodeMetrics.cpp
   ConstantFolding.cpp
   DIBuilder.cpp
   DbgInfoPrinter.cpp