Bug 1289457 - Take advantage of infallible new in XPCNativeSet::NewInstance{,Mutate} to skip checks. r=mrbkap

MozReview-Commit-ID: H4TEMzzT6iK

js/xpconnect/src/XPCWrappedNativeInfo.cpp

@@ -680,8 +680,6 @@ XPCNativeSet*
 XPCNativeSet::NewInstance(XPCNativeInterface** array,
                           uint16_t count)
 {
-    XPCNativeSet* obj = nullptr;
-
     if (!array || !count)
         return nullptr;
 
@@ -707,10 +705,8 @@ XPCNativeSet::NewInstance(XPCNativeInterface** array,
     if (slots > 1)
         size += (slots - 1) * sizeof(XPCNativeInterface*);
     void* place = new char[size];
-    if (place)
+    XPCNativeSet* obj = new(place) XPCNativeSet();
-        obj = new(place) XPCNativeSet();
 
-    if (obj) {
     // Stick the nsISupports in front and skip additional nsISupport(s)
     XPCNativeInterface** inp = array;
     XPCNativeInterface** outp = (XPCNativeInterface**) &obj->mInterfaces;
@@ -728,7 +724,6 @@ XPCNativeSet::NewInstance(XPCNativeInterface** array,
     }
     obj->mMemberCount = memberCount;
     obj->mInterfaceCount = slots;
-    }
 
     return obj;
 }
@@ -739,8 +734,6 @@ XPCNativeSet::NewInstanceMutate(XPCNativeSet*       otherSet,
                                 XPCNativeInterface* newInterface,
                                 uint16_t            position)
 {
-    XPCNativeSet* obj = nullptr;
-
     if (!newInterface)
         return nullptr;
     if (otherSet && position > otherSet->mInterfaceCount)
@@ -752,10 +745,8 @@ XPCNativeSet::NewInstanceMutate(XPCNativeSet*       otherSet,
     if (otherSet)
         size += otherSet->mInterfaceCount * sizeof(XPCNativeInterface*);
     void* place = new char[size];
-    if (place)
+    XPCNativeSet* obj = new(place) XPCNativeSet();
-        obj = new(place) XPCNativeSet();
 
-    if (obj) {
     if (otherSet) {
         obj->mMemberCount = otherSet->GetMemberCount() +
             newInterface->GetMemberCount();
@@ -774,7 +765,6 @@ XPCNativeSet::NewInstanceMutate(XPCNativeSet*       otherSet,
         obj->mInterfaceCount = 1;
         obj->mInterfaces[0] = newInterface;
     }
-    }
 
     return obj;
 }