Re-land "[ThinLTO] Add call edges' relative block frequency to per-module summary."

It was reverted after buildbot regressions.

Original commit message:

This allows relative block frequency of call edges to be passed
to the thinlink stage where it will be used to compute synthetic
entry counts of functions.

llvm-svn: 323460
diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index b1eefb9..ed85c20 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -269,7 +269,7 @@
     };
 
     const auto NewThreshold =
-        Threshold * GetBonusMultiplier(Edge.second.Hotness);
+        Threshold * GetBonusMultiplier(Edge.second.getHotness());
 
     auto *CalleeSummary = selectCallee(Index, VI.getSummaryList(), NewThreshold,
                                        Summary.modulePath());
@@ -293,7 +293,8 @@
       return Threshold * ImportInstrFactor;
     };
 
-    bool IsHotCallsite = Edge.second.Hotness == CalleeInfo::HotnessType::Hot;
+    bool IsHotCallsite =
+        Edge.second.getHotness() == CalleeInfo::HotnessType::Hot;
     const auto AdjThreshold = GetAdjustedThreshold(Threshold, IsHotCallsite);
 
     auto ExportModulePath = ResolvedCalleeSummary->modulePath();