Refactor profile summary support code. NFC.

Summary computation is not just for instrumented profiling and so I have moved
the ProfileSummary class to ProfileCommon.h (named so to allow code unrelated
to summary but common to instrumented and sampled profiling to be placed there)

Differential Revision: http://reviews.llvm.org/D16661

llvm-svn: 259846
diff --git a/llvm/tools/llvm-profdata/llvm-profdata.cpp b/llvm/tools/llvm-profdata/llvm-profdata.cpp
index 9d926531..2b6eacf 100644
--- a/llvm/tools/llvm-profdata/llvm-profdata.cpp
+++ b/llvm/tools/llvm-profdata/llvm-profdata.cpp
@@ -17,6 +17,7 @@
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/ProfileData/InstrProfReader.h"
 #include "llvm/ProfileData/InstrProfWriter.h"
+#include "llvm/ProfileData/ProfileCommon.h"
 #include "llvm/ProfileData/SampleProfReader.h"
 #include "llvm/ProfileData/SampleProfWriter.h"
 #include "llvm/Support/CommandLine.h"