Bug 1189750 - Fix JSScript::getPCCounts to return a reference instead of a copy. r=bhackett

js/src/jsscript.cpp

@@ -1324,7 +1324,7 @@ static inline ScriptCountsMap::Ptr GetScriptCountsMapEntry(JSScript* script)
     return p;
 }
 
-js::PCCounts
+js::PCCounts&
 JSScript::getPCCounts(jsbytecode* pc) {
     MOZ_ASSERT(containsPC(pc));
     ScriptCountsMap::Ptr p = GetScriptCountsMapEntry(this);

js/src/jsscript.h

@@ -1629,7 +1629,7 @@ class JSScript : public js::gc::TenuredCell
 
   public:
     bool initScriptCounts(JSContext* cx);
-    js::PCCounts getPCCounts(jsbytecode* pc);
+    js::PCCounts& getPCCounts(jsbytecode* pc);
     void addIonCounts(js::jit::IonScriptCounts* ionCounts);
     js::jit::IonScriptCounts* getIonCounts();
     js::ScriptCounts releaseScriptCounts();