--- a/content/base/src/nsFrameLoader.cpp
+++ b/content/base/src/nsFrameLoader.cpp
@@ -1567,17 +1567,17 @@ nsFrameLoader::MaybeCreateDocShell()
     // XXX if no NAME then use ID, after a transition period this will be
     // changed so that XUL only uses ID too (bug 254284).
     if (frameName.IsEmpty() && namespaceID == kNameSpaceID_XUL) {
       mOwnerContent->GetAttr(kNameSpaceID_None, nsGkAtoms::id, frameName);
     }
   }
 
   if (!frameName.IsEmpty()) {
-    mDocShell->SetName(frameName.get());
+    mDocShell->SetName(frameName);
   }
 
   // If our container is a web-shell, inform it that it has a new
   // child. If it's not a web-shell then some things will not operate
   // properly.
 
   nsCOMPtr<nsIDocShellTreeNode> parentAsNode(do_QueryInterface(parentAsWebNav));
   if (parentAsNode) {

--- a/content/html/content/src/nsGenericHTMLFrameElement.cpp
+++ b/content/html/content/src/nsGenericHTMLFrameElement.cpp
@@ -228,17 +228,17 @@ nsGenericHTMLFrameElement::SetAttr(int32
     // what we should reflect.
     LoadSrc();
   } else if (aNameSpaceID == kNameSpaceID_None && aName == nsGkAtoms::name) {
     // Propagate "name" to the docshell to make browsing context names live,
     // per HTML5.
     nsIDocShell *docShell = mFrameLoader ? mFrameLoader->GetExistingDocShell()
                                          : nullptr;
     if (docShell) {
-      docShell->SetName(PromiseFlatString(aValue).get());
+      docShell->SetName(aValue);
     }
   }
 
   return NS_OK;
 }
 
 nsresult
 nsGenericHTMLFrameElement::UnsetAttr(int32_t aNameSpaceID, nsIAtom* aAttribute,
@@ -249,17 +249,17 @@ nsGenericHTMLFrameElement::UnsetAttr(int
   NS_ENSURE_SUCCESS(rv, rv);
 
   if (aNameSpaceID == kNameSpaceID_None && aAttribute == nsGkAtoms::name) {
     // Propagate "name" to the docshell to make browsing context names live,
     // per HTML5.
     nsIDocShell *docShell = mFrameLoader ? mFrameLoader->GetExistingDocShell()
                                          : nullptr;
     if (docShell) {
-      docShell->SetName(EmptyString().get());
+      docShell->SetName(EmptyString());
     }
   }
 
   return NS_OK;
 }
 
 void
 nsGenericHTMLFrameElement::DestroyContent()

--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -2811,27 +2811,26 @@ nsDocShell::GetCurrentDocChannel()
     return nullptr;
 }
 
 //*****************************************************************************
 // nsDocShell::nsIDocShellTreeItem
 //*****************************************************************************   
 
 NS_IMETHODIMP
-nsDocShell::GetName(PRUnichar ** aName)
-{
-    NS_ENSURE_ARG_POINTER(aName);
-    *aName = ToNewUnicode(mName);
-    return NS_OK;
-}
-
-NS_IMETHODIMP
-nsDocShell::SetName(const PRUnichar * aName)
-{
-    mName = aName;              // this does a copy of aName
+nsDocShell::GetName(nsAString& aName)
+{
+    aName = mName;
+    return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShell::SetName(const nsAString& aName)
+{
+    mName = aName;
     return NS_OK;
 }
 
 NS_IMETHODIMP
 nsDocShell::NameEquals(const PRUnichar *aName, bool *_retval)
 {
     NS_ENSURE_ARG_POINTER(aName);
     NS_ENSURE_ARG_POINTER(_retval);

--- a/docshell/base/nsIDocShellTreeItem.idl
+++ b/docshell/base/nsIDocShellTreeItem.idl
@@ -10,23 +10,23 @@ interface nsIDocShellTreeOwner;
 
 
 /**
  * The nsIDocShellTreeItem supplies the methods that are required of any item
  * that wishes to be able to live within the docshell tree either as a middle
  * node or a leaf. 
  */
 
-[scriptable, uuid(09b54ec1-d98a-49a9-bc95-3219e8b55089)]
+[scriptable, uuid(e35bbb39-985b-4d62-81da-73c330222e5f)]
 interface nsIDocShellTreeItem : nsIDocShellTreeNode
 {
 	/*
 	name of the DocShellTreeItem
 	*/
-	attribute wstring name;
+	attribute AString name;
 
         /**
          * Compares the provided name against the item's name and
          * returns the appropriate result.
          *
          * @return <CODE>PR_TRUE</CODE> if names match;
          *         <CODE>PR_FALSE</CODE> otherwise.
          */

--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -3769,32 +3769,30 @@ nsGlobalWindow::SetDefaultStatus(const n
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsGlobalWindow::GetName(nsAString& aName)
 {
   FORWARD_TO_OUTER(GetName, (aName), NS_ERROR_NOT_INITIALIZED);
 
-  nsXPIDLString name;
   if (mDocShell)
-    mDocShell->GetName(getter_Copies(name));
-
-  aName.Assign(name);
+    mDocShell->GetName(aName);
+
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsGlobalWindow::SetName(const nsAString& aName)
 {
   FORWARD_TO_OUTER(SetName, (aName), NS_ERROR_NOT_INITIALIZED);
 
   nsresult result = NS_OK;
   if (mDocShell)
-    result = mDocShell->SetName(PromiseFlatString(aName).get());
+    result = mDocShell->SetName(aName);
   return result;
 }
 
 // Helper functions used by many methods below.
 int32_t
 nsGlobalWindow::DevToCSSIntPixels(int32_t px)
 {
   if (!mDocShell)

--- a/embedding/browser/webBrowser/nsWebBrowser.cpp
+++ b/embedding/browser/webBrowser/nsWebBrowser.cpp
@@ -395,29 +395,27 @@ NS_IMETHODIMP nsWebBrowser::SetIsActive(
     return mDocShell->SetIsActive(aIsActive);
   return NS_OK;
 }
 
 //*****************************************************************************
 // nsWebBrowser::nsIDocShellTreeItem
 //*****************************************************************************   
 
-NS_IMETHODIMP nsWebBrowser::GetName(PRUnichar** aName)
+NS_IMETHODIMP nsWebBrowser::GetName(nsAString& aName)
 {
-   NS_ENSURE_ARG_POINTER(aName);
-
    if(mDocShell)  
       mDocShell->GetName(aName);
    else
-      *aName = ToNewUnicode(mInitInfo->name);
+      aName = mInitInfo->name;
 
    return NS_OK;
 }
 
-NS_IMETHODIMP nsWebBrowser::SetName(const PRUnichar* aName)
+NS_IMETHODIMP nsWebBrowser::SetName(const nsAString& aName)
 {
    if(mDocShell)
       {
       return mDocShell->SetName(aName);
       }
    else
       mInitInfo->name = aName;
 
@@ -1166,17 +1164,17 @@ NS_IMETHODIMP nsWebBrowser::Create()
    (void)mDocShellTreeOwner->QueryInterface(NS_GET_IID(nsIWebProgressListener),
                              static_cast<void**>(getter_AddRefs(supports)));
    (void)BindListener(supports, NS_GET_IID(nsIWebProgressListener));
 
    NS_ENSURE_SUCCESS(mDocShellAsWin->InitWindow(nullptr,
       docShellParentWidget, mInitInfo->x, mInitInfo->y, mInitInfo->cx,
       mInitInfo->cy), NS_ERROR_FAILURE);
 
-   mDocShell->SetName(mInitInfo->name.get());
+   mDocShell->SetName(mInitInfo->name);
    if (mContentType == typeChromeWrapper)
    {
        mDocShell->SetItemType(nsIDocShellTreeItem::typeChrome);
    }
    else
    {
        mDocShell->SetItemType(nsIDocShellTreeItem::typeContent);
    }

--- a/embedding/components/windowwatcher/src/nsWindowWatcher.cpp
+++ b/embedding/components/windowwatcher/src/nsWindowWatcher.cpp
@@ -800,21 +800,23 @@ nsWindowWatcher::OpenWindowInternal(nsID
 
     rv = piwin->SetArguments(argv, callerPrincipal);
     NS_ENSURE_SUCCESS(rv, rv);
   }
 
   /* allow a window that we found by name to keep its name (important for cases
      like _self where the given name is different (and invalid)).  Also, _blank
      is not a window name. */
-  if (windowNeedsName)
-    newDocShellItem->SetName(nameSpecified &&
-                             !name.LowerCaseEqualsLiteral("_blank") ?
-                             name.get() : nullptr);
-
+  if (windowNeedsName) {
+    if (nameSpecified && !name.LowerCaseEqualsLiteral("_blank")) {
+      newDocShellItem->SetName(name);
+    } else {
+      newDocShellItem->SetName(EmptyString());
+    }
+  }
 
   // Inherit the right character set into the new window to use as a fallback
   // in the event the document being loaded does not specify a charset.  When
   // aCalledFromJS is true, we want to use the character set of the document in
   // the caller; otherwise we want to use the character set of aParent's
   // docshell. Failing to set this charset is not fatal, so we want to continue
   // in the face of errors.
   nsCOMPtr<nsIContentViewer> newCV;