Bug 1276327. Remove the non-debug use of CxPusherIsStackTop(). r=bholley

dom/base/ScriptSettings.cpp

@@ -268,29 +268,6 @@ GetWebIDLCallerPrincipal()
   }
   AutoEntryScript* aes = static_cast<AutoEntryScript*>(entry);
 
-  // We can't yet rely on the Script Settings Stack to properly determine the
-  // entry script, because there are still lots of places in the tree where we
-  // don't yet use an AutoEntryScript (bug 951991 tracks this work). In the
-  // mean time though, we can make some observations to hack around the
-  // problem:
-  //
-  // (1) All calls into JS-implemented WebIDL go through CallSetup, which goes
-  //     through AutoEntryScript.
-  // (2) The top candidate entry point in the Script Settings Stack is the
-  //     entry point if and only if no other JSContexts have been pushed on
-  //     top of the push made by that entry's AutoEntryScript.
-  //
-  // Because of (1), all of the cases where we might return a non-null
-  // WebIDL Caller are guaranteed to have put an entry on the Script Settings
-  // Stack, so we can restrict our search to that. Moreover, (2) gives us a
-  // criterion to determine whether an entry in the Script Setting Stack means
-  // that we should return a non-null WebIDL Caller.
-  //
-  // Once we fix bug 951991, this can all be simplified.
-  if (!aes->CxPusherIsStackTop()) {
-    return nullptr;
-  }
-
   return aes->mWebIDLCallerPrincipal;
 }
 
@@ -755,9 +732,9 @@ danger::AutoCxPusher::AutoCxPusher(JSContext* cx, bool allowNull)
 
   XPCJSContextStack *stack = XPCJSRuntime::Get()->GetJSContextStack();
   stack->Push(cx);
-  mStackDepthAfterPush = stack->Count();
 
 #ifdef DEBUG
+  mStackDepthAfterPush = stack->Count();
   mPushedContext = cx;
   mCompartmentDepthOnEntry = cx ? js::GetEnterCompartmentDepth(cx) : 0;
 #endif
@@ -781,11 +758,11 @@ danger::AutoCxPusher::~AutoCxPusher()
   // pop is the same as it was right after we pushed.
   MOZ_ASSERT_IF(mPushedContext, mCompartmentDepthOnEntry ==
                                 js::GetEnterCompartmentDepth(mPushedContext));
-  DebugOnly<JSContext*> stackTop;
   MOZ_ASSERT(mPushedContext == nsXPConnect::XPConnect()->GetCurrentJSContext());
   XPCJSRuntime::Get()->GetJSContextStack()->Pop();
 }
 
+#ifdef DEBUG
 bool
 danger::AutoCxPusher::IsStackTop() const
 {
@@ -793,6 +770,7 @@ danger::AutoCxPusher::IsStackTop() const
   MOZ_ASSERT(currentDepth >= mStackDepthAfterPush);
   return currentDepth == mStackDepthAfterPush;
 }
+#endif
 
 } // namespace dom
 

dom/base/ScriptSettings.h

@@ -46,8 +46,8 @@ public:
 
 private:
   mozilla::Maybe<JSAutoRequest> mAutoRequest;
-  uint32_t mStackDepthAfterPush;
 #ifdef DEBUG
+  uint32_t mStackDepthAfterPush;
   JSContext* mPushedContext;
   unsigned mCompartmentDepthOnEntry;
 #endif
@@ -262,7 +262,9 @@ public:
     return mCx;
   }
 
+#ifdef DEBUG
   bool CxPusherIsStackTop() const { return mCxPusher->IsStackTop(); }
+#endif
 
   // If HasException, report it.  Otherwise, a no-op.
   void ReportException();