--- a/accessible/src/atk/AccessibleWrap.cpp
+++ b/accessible/src/atk/AccessibleWrap.cpp
@@ -719,17 +719,17 @@ ConvertToAtkAttributeSet(nsIPersistentPr
     while (NS_SUCCEEDED(propEnum->HasMoreElements(&hasMore)) && hasMore) {
         nsCOMPtr<nsISupports> sup;
         rv = propEnum->GetNext(getter_AddRefs(sup));
         NS_ENSURE_SUCCESS(rv, objAttributeSet);
 
         nsCOMPtr<nsIPropertyElement> propElem(do_QueryInterface(sup));
         NS_ENSURE_TRUE(propElem, objAttributeSet);
 
-        nsCAutoString name;
+        nsAutoCString name;
         rv = propElem->GetKey(name);
         NS_ENSURE_SUCCESS(rv, objAttributeSet);
 
         nsAutoString value;
         rv = propElem->GetValue(value);
         NS_ENSURE_SUCCESS(rv, objAttributeSet);
 
         AtkAttribute *objAttr = (AtkAttribute *)g_malloc(sizeof(AtkAttribute));

--- a/accessible/src/atk/ApplicationAccessibleWrap.cpp
+++ b/accessible/src/atk/ApplicationAccessibleWrap.cpp
@@ -781,34 +781,34 @@ LoadGtkModule(GnomeAccessibilityModule& 
     NS_ENSURE_ARG(aModule.libName);
 
     if (!(aModule.lib = PR_LoadLibrary(aModule.libName))) {
 
         MAI_LOG_DEBUG(("Fail to load lib: %s in default path\n", aModule.libName));
 
         //try to load the module with "gtk-2.0/modules" appended
         char *curLibPath = PR_GetLibraryPath();
-        nsCAutoString libPath(curLibPath);
+        nsAutoCString libPath(curLibPath);
 #if defined(LINUX) && defined(__x86_64__)
         libPath.Append(":/usr/lib64:/usr/lib");
 #else
         libPath.Append(":/usr/lib");
 #endif
         MAI_LOG_DEBUG(("Current Lib path=%s\n", libPath.get()));
         PR_FreeLibraryName(curLibPath);
 
         int16_t loc1 = 0, loc2 = 0;
         int16_t subLen = 0;
         while (loc2 >= 0) {
             loc2 = libPath.FindChar(':', loc1);
             if (loc2 < 0)
                 subLen = libPath.Length() - loc1;
             else
                 subLen = loc2 - loc1;
-            nsCAutoString sub(Substring(libPath, loc1, subLen));
+            nsAutoCString sub(Substring(libPath, loc1, subLen));
             sub.Append("/gtk-2.0/modules/");
             sub.Append(aModule.libName);
             aModule.lib = PR_LoadLibrary(sub.get());
             if (aModule.lib) {
                 MAI_LOG_DEBUG(("Ok, load %s from %s\n", aModule.libName, sub.get()));
                 break;
             }
             loc1 = loc2+1;

--- a/accessible/src/atk/nsMaiHyperlink.cpp
+++ b/accessible/src/atk/nsMaiHyperlink.cpp
@@ -181,17 +181,17 @@ getUriCB(AtkHyperlink *aLink, gint aLink
 {
     Accessible* hyperlink = get_accessible_hyperlink(aLink);
     NS_ENSURE_TRUE(hyperlink, nullptr);
 
     nsCOMPtr<nsIURI> uri = hyperlink->AnchorURIAt(aLinkIndex);
     if (!uri)
         return nullptr;
 
-    nsCAutoString cautoStr;
+    nsAutoCString cautoStr;
     nsresult rv = uri->GetSpec(cautoStr);
     NS_ENSURE_SUCCESS(rv, nullptr);
 
     return g_strdup(cautoStr.get());
 }
 
 AtkObject *
 getObjectCB(AtkHyperlink *aLink, gint aLinkIndex)

--- a/accessible/src/base/FocusManager.h
+++ b/accessible/src/base/FocusManager.h
@@ -151,27 +151,27 @@ private:
     uint32_t msecs = PR_IntervalToMilliseconds(time) % 1000;                   \
     printf("Time: %2d:%2d.%3d\n", mins, secs, msecs);                          \
   }
 
 #define A11YDEBUG_FOCUS_LOG_DOMNODE(aNode)                                     \
   if (aNode) {                                                                 \
     if (aNode->IsElement()) {                                                  \
       dom::Element* targetElm = aNode->AsElement();                            \
-      nsCAutoString tag;                                                       \
+      nsAutoCString tag;                                                       \
       targetElm->Tag()->ToUTF8String(tag);                                     \
-      nsCAutoString id;                                                        \
+      nsAutoCString id;                                                        \
       nsIAtom* atomid = targetElm->GetID();                                    \
       if (atomid)                                                              \
         atomid->ToUTF8String(id);                                              \
       printf("element %s@id='%s': %p", tag.get(), id.get(), (void*)aNode);     \
     } else if (aNode->IsNodeOfType(nsINode::eDOCUMENT)) {                      \
       nsCOMPtr<nsIDocument> document = do_QueryInterface(aNode);               \
       nsIURI* uri = document->GetDocumentURI();                                \
-      nsCAutoString spec;                                                      \
+      nsAutoCString spec;                                                      \
       uri->GetSpec(spec);                                                      \
       printf("document: %p; uri: %s", (void*)aNode, spec.get());               \
     }                                                                          \
   }
 
 #define A11YDEBUG_FOCUS_LOG_ACCESSIBLE(aAccessible)                            \
   printf("accessible: %p; ", (void*)aAccessible);                              \
   if (aAccessible) {                                                           \

--- a/accessible/src/base/Logging.cpp
+++ b/accessible/src/base/Logging.cpp
@@ -75,27 +75,27 @@ EnableLogging(const char* aModulesStr)
       token++; // skip ',' char
   }
 }
 
 static void
 LogDocURI(nsIDocument* aDocumentNode)
 {
   nsIURI* uri = aDocumentNode->GetDocumentURI();
-  nsCAutoString spec;
+  nsAutoCString spec;
   uri->GetSpec(spec);
   printf("uri: %s", spec.get());
 }
 
 static void
 LogDocShellState(nsIDocument* aDocumentNode)
 {
   printf("docshell busy: ");
 
-  nsCAutoString docShellBusy;
+  nsAutoCString docShellBusy;
   nsCOMPtr<nsISupports> container = aDocumentNode->GetContainer();
   if (container) {
     nsCOMPtr<nsIDocShell> docShell = do_QueryInterface(container);
     uint32_t busyFlags = nsIDocShell::BUSY_FLAGS_NONE;
     docShell->GetBusyFlags(&busyFlags);
     if (busyFlags == nsIDocShell::BUSY_FLAGS_NONE)
       printf("'none'");
     if (busyFlags & nsIDocShell::BUSY_FLAGS_BUSY)
@@ -291,17 +291,17 @@ LogShellLoadType(nsIDocShell* aDocShell)
       printf("unknown");
   }
 }
 
 static void
 LogRequest(nsIRequest* aRequest)
 {
   if (aRequest) {
-    nsCAutoString name;
+    nsAutoCString name;
     aRequest->GetName(name);
     printf("    request spec: %s\n", name.get());
     uint32_t loadFlags = 0;
     aRequest->GetLoadFlags(&loadFlags);
     printf("    request load flags: %x; ", loadFlags);
     if (loadFlags & nsIChannel::LOAD_DOCUMENT_URI)
       printf("document uri; ");
     if (loadFlags & nsIChannel::LOAD_RETARGETED_DOCUMENT_URI)
@@ -402,26 +402,26 @@ logging::DocLoad(const char* aMsg, nsIDo
   LogDocInfo(aDocumentNode, document);
 
   MsgEnd();
 }
 
 void
 logging::DocLoadEventFired(AccEvent* aEvent)
 {
-  nsCAutoString strEventType;
+  nsAutoCString strEventType;
   GetDocLoadEventType(aEvent, strEventType);
   if (!strEventType.IsEmpty())
     printf("  fire: %s\n", strEventType.get());
 }
 
 void
 logging::DocLoadEventHandled(AccEvent* aEvent)
 {
-  nsCAutoString strEventType;
+  nsAutoCString strEventType;
   GetDocLoadEventType(aEvent, strEventType);
   if (strEventType.IsEmpty())
     return;
 
   MsgBegin(sDocEventTitle, "handled '%s' event", strEventType.get());
 
   nsINode* node = aEvent->GetNode();
   if (node->IsNodeOfType(nsINode::eDOCUMENT)) {
@@ -569,21 +569,21 @@ logging::Node(const char* aDescr, nsINod
   if (!aNode->IsElement()) {
     printf("%s: %p, not accessible node type, idx in parent: %d\n",
            aDescr, static_cast<void*>(aNode), idxInParent);
     return;
   }
 
   dom::Element* elm = aNode->AsElement();
 
-  nsCAutoString tag;
+  nsAutoCString tag;
   elm->Tag()->ToUTF8String(tag);
 
   nsIAtom* idAtom = elm->GetID();
-  nsCAutoString id;
+  nsAutoCString id;
   if (idAtom)
     idAtom->ToUTF8String(id);
 
   printf("%s: %p, %s@id='%s', idx in parent: %d\n",
          aDescr, static_cast<void*>(elm), tag.get(), id.get(), idxInParent);
 }
 
 void

--- a/accessible/src/base/nsAccUtils.cpp
+++ b/accessible/src/base/nsAccUtils.cpp
@@ -35,17 +35,17 @@ nsAccUtils::GetAccAttr(nsIPersistentProp
   aAttributes->GetStringProperty(nsAtomCString(aAttrName), aAttrValue);
 }
 
 void
 nsAccUtils::SetAccAttr(nsIPersistentProperties *aAttributes,
                        nsIAtom *aAttrName, const nsAString& aAttrValue)
 {
   nsAutoString oldValue;
-  nsCAutoString attrName;
+  nsAutoCString attrName;
 
   aAttributes->SetStringProperty(nsAtomCString(aAttrName), aAttrValue, oldValue);
 }
 
 void
 nsAccUtils::SetAccGroupAttrs(nsIPersistentProperties *aAttributes,
                              int32_t aLevel, int32_t aSetSize,
                              int32_t aPosInSet)

--- a/accessible/src/base/nsCoreUtils.cpp
+++ b/accessible/src/base/nsCoreUtils.cpp
@@ -470,17 +470,17 @@ bool
 nsCoreUtils::IsErrorPage(nsIDocument *aDocument)
 {
   nsIURI *uri = aDocument->GetDocumentURI();
   bool isAboutScheme = false;
   uri->SchemeIs("about", &isAboutScheme);
   if (!isAboutScheme)
     return false;
 
-  nsCAutoString path;
+  nsAutoCString path;
   uri->GetPath(path);
 
   NS_NAMED_LITERAL_CSTRING(neterror, "neterror");
   NS_NAMED_LITERAL_CSTRING(certerror, "certerror");
 
   return StringBeginsWith(path, neterror) || StringBeginsWith(path, certerror);
 }
 

--- a/accessible/src/generic/ApplicationAccessible.cpp
+++ b/accessible/src/generic/ApplicationAccessible.cpp
@@ -213,33 +213,33 @@ ApplicationAccessible::DoAction(uint8_t 
 NS_IMETHODIMP
 ApplicationAccessible::GetAppName(nsAString& aName)
 {
   aName.Truncate();
 
   if (!mAppInfo)
     return NS_ERROR_FAILURE;
 
-  nsCAutoString cname;
+  nsAutoCString cname;
   nsresult rv = mAppInfo->GetName(cname);
   NS_ENSURE_SUCCESS(rv, rv);
 
   AppendUTF8toUTF16(cname, aName);
   return NS_OK;
 }
 
 NS_IMETHODIMP
 ApplicationAccessible::GetAppVersion(nsAString& aVersion)
 {
   aVersion.Truncate();
 
   if (!mAppInfo)
     return NS_ERROR_FAILURE;
 
-  nsCAutoString cversion;
+  nsAutoCString cversion;
   nsresult rv = mAppInfo->GetVersion(cversion);
   NS_ENSURE_SUCCESS(rv, rv);
 
   AppendUTF8toUTF16(cversion, aVersion);
   return NS_OK;
 }
 
 NS_IMETHODIMP
@@ -252,17 +252,17 @@ ApplicationAccessible::GetPlatformName(n
 NS_IMETHODIMP
 ApplicationAccessible::GetPlatformVersion(nsAString& aVersion)
 {
   aVersion.Truncate();
 
   if (!mAppInfo)
     return NS_ERROR_FAILURE;
 
-  nsCAutoString cversion;
+  nsAutoCString cversion;
   nsresult rv = mAppInfo->GetPlatformVersion(cversion);
   NS_ENSURE_SUCCESS(rv, rv);
 
   AppendUTF8toUTF16(cversion, aVersion);
   return NS_OK;
 }
 
 ////////////////////////////////////////////////////////////////////////////////

--- a/accessible/src/generic/DocAccessible.cpp
+++ b/accessible/src/generic/DocAccessible.cpp
@@ -381,17 +381,17 @@ DocAccessible::TakeFocus()
 NS_IMETHODIMP
 DocAccessible::GetURL(nsAString& aURL)
 {
   if (IsDefunct())
     return NS_ERROR_FAILURE;
 
   nsCOMPtr<nsISupports> container = mDocument->GetContainer();
   nsCOMPtr<nsIWebNavigation> webNav(do_GetInterface(container));
-  nsCAutoString theURL;
+  nsAutoCString theURL;
   if (webNav) {
     nsCOMPtr<nsIURI> pURI;
     webNav->GetCurrentURI(getter_AddRefs(pURI));
     if (pURI)
       pURI->GetSpec(theURL);
   }
   CopyUTF8toUTF16(theURL, aURL);
   return NS_OK;

--- a/accessible/src/generic/ImageAccessible.cpp
+++ b/accessible/src/generic/ImageAccessible.cpp
@@ -131,17 +131,17 @@ ImageAccessible::DoAction(uint8_t aIndex
   // Get the long description uri and open in a new window.
   if (!IsLongDescIndex(aIndex))
     return LinkableAccessible::DoAction(aIndex);
 
   nsCOMPtr<nsIURI> uri = GetLongDescURI();
   if (!uri)
     return NS_ERROR_INVALID_ARG;
 
-  nsCAutoString utf8spec;
+  nsAutoCString utf8spec;
   uri->GetSpec(utf8spec);
   NS_ConvertUTF8toUTF16 spec(utf8spec);
 
   nsIDocument* document = mContent->OwnerDoc();
   nsCOMPtr<nsPIDOMWindow> piWindow = document->GetWindow();
   nsCOMPtr<nsIDOMWindow> win = do_QueryInterface(piWindow);
   NS_ENSURE_STATE(win);
 

--- a/accessible/src/msaa/AccessibleWrap.cpp
+++ b/accessible/src/msaa/AccessibleWrap.cpp
@@ -1563,17 +1563,17 @@ AccessibleWrap::FirePlatformEvent(AccEve
   int32_t childID = GetChildIDFor(accessible); // get the id for the accessible
   if (!childID)
     return NS_OK; // Can't fire an event without a child ID
 
   HWND hWnd = GetHWNDFor(accessible);
   NS_ENSURE_TRUE(hWnd, NS_ERROR_FAILURE);
 
   nsAutoString tag;
-  nsCAutoString id;
+  nsAutoCString id;
   nsIContent* cnt = accessible->GetContent();
   if (cnt) {
     cnt->Tag()->ToString(tag);
     nsIAtom* aid = cnt->GetID();
     if (aid)
       aid->ToUTF8String(id);
   }
 
@@ -1673,17 +1673,17 @@ AccessibleWrap::ConvertToIA2Attributes(n
   while (NS_SUCCEEDED(propEnum->HasMoreElements(&hasMore)) && hasMore) {
     nsCOMPtr<nsISupports> propSupports;
     propEnum->GetNext(getter_AddRefs(propSupports));
 
     nsCOMPtr<nsIPropertyElement> propElem(do_QueryInterface(propSupports));
     if (!propElem)
       return E_FAIL;
 
-    nsCAutoString name;
+    nsAutoCString name;
     if (NS_FAILED(propElem->GetKey(name)))
       return E_FAIL;
 
     uint32_t offset = 0;
     while ((offset = name.FindCharInSet(kCharsToEscape, offset)) != kNotFound) {
       name.Insert('\\', offset);
       offset += 2;
     }

--- a/accessible/src/msaa/ia2AccessibleHyperlink.cpp
+++ b/accessible/src/msaa/ia2AccessibleHyperlink.cpp
@@ -83,22 +83,22 @@ ia2AccessibleHyperlink::get_anchorTarget
 
   if (!thisObj->IsLink())
     return S_FALSE;
 
   nsCOMPtr<nsIURI> uri = thisObj->AnchorURIAt(aIndex);
   if (!uri)
     return S_FALSE;
 
-  nsCAutoString prePath;
+  nsAutoCString prePath;
   nsresult rv = uri->GetPrePath(prePath);
   if (NS_FAILED(rv))
     return GetHRESULT(rv);
 
-  nsCAutoString path;
+  nsAutoCString path;
   rv = uri->GetPath(path);
   if (NS_FAILED(rv))
     return GetHRESULT(rv);
 
   nsAutoString stringURI;
   AppendUTF8toUTF16(prePath, stringURI);
   AppendUTF8toUTF16(path, stringURI);
 

--- a/accessible/src/xul/XULTreeAccessible.cpp
+++ b/accessible/src/xul/XULTreeAccessible.cpp
@@ -194,17 +194,17 @@ XULTreeAccessible::ChildAtPoint(int32_t 
 
   nsIntRect rootRect = rootFrame->GetScreenRect();
 
   int32_t clientX = presContext->DevPixelsToIntCSSPixels(aX) - rootRect.x;
   int32_t clientY = presContext->DevPixelsToIntCSSPixels(aY) - rootRect.y;
 
   int32_t row = -1;
   nsCOMPtr<nsITreeColumn> column;
-  nsCAutoString childEltUnused;
+  nsAutoCString childEltUnused;
   mTree->GetCellAt(clientX, clientY, &row, getter_AddRefs(column),
                    childEltUnused);
 
   // If we failed to find tree cell for the given point then it might be
   // tree columns.
   if (row == -1 || !column)
     return AccessibleWrap::ChildAtPoint(aX, aY, aWhichChild);
 
@@ -1023,17 +1023,17 @@ XULTreeItemAccessibleBase::DispatchClick
 
   nsCOMPtr<nsITreeColumns> columns;
   mTree->GetColumns(getter_AddRefs(columns));
   if (!columns)
     return;
 
   // Get column and pseudo element.
   nsCOMPtr<nsITreeColumn> column;
-  nsCAutoString pseudoElm;
+  nsAutoCString pseudoElm;
 
   if (aActionIndex == eAction_Click) {
     // Key column is visible and clickable.
     columns->GetKeyColumn(getter_AddRefs(column));
   } else {
     // Primary column contains a twisty we should click on.
     columns->GetPrimaryColumn(getter_AddRefs(column));
     pseudoElm = NS_LITERAL_CSTRING("twisty");

--- a/accessible/src/xul/XULTreeGridAccessible.cpp
+++ b/accessible/src/xul/XULTreeGridAccessible.cpp
@@ -362,17 +362,17 @@ XULTreeGridRowAccessible::ChildAtPoint(i
 
   nsIntRect rootRect = rootFrame->GetScreenRect();
 
   int32_t clientX = presContext->DevPixelsToIntCSSPixels(aX) - rootRect.x;
   int32_t clientY = presContext->DevPixelsToIntCSSPixels(aY) - rootRect.y;
 
   int32_t row = -1;
   nsCOMPtr<nsITreeColumn> column;
-  nsCAutoString childEltUnused;
+  nsAutoCString childEltUnused;
   mTree->GetCellAt(clientX, clientY, &row, getter_AddRefs(column),
                    childEltUnused);
 
   // Return if we failed to find tree cell in the row for the given point.
   if (row != mRow || !column)
     return nullptr;
 
   return GetCellAccessible(column);

--- a/browser/components/about/AboutRedirector.cpp
+++ b/browser/components/about/AboutRedirector.cpp
@@ -75,20 +75,20 @@ static RedirEntry kRedirMap[] = {
     nsIAboutModule::ALLOW_SCRIPT },
   { "permissions", "chrome://browser/content/preferences/aboutPermissions.xul",
     nsIAboutModule::ALLOW_SCRIPT },
   { "preferences", "chrome://browser/content/preferences/in-content/preferences.xul",
     nsIAboutModule::ALLOW_SCRIPT },
 };
 static const int kRedirTotal = NS_ARRAY_LENGTH(kRedirMap);
 
-static nsCAutoString
+static nsAutoCString
 GetAboutModuleName(nsIURI *aURI)
 {
-  nsCAutoString path;
+  nsAutoCString path;
   aURI->GetPath(path);
 
   int32_t f = path.FindChar('#');
   if (f >= 0)
     path.SetLength(f);
 
   f = path.FindChar('?');
   if (f >= 0)
@@ -99,17 +99,17 @@ GetAboutModuleName(nsIURI *aURI)
 }
 
 NS_IMETHODIMP
 AboutRedirector::NewChannel(nsIURI *aURI, nsIChannel **result) 
 {
   NS_ENSURE_ARG_POINTER(aURI);
   NS_ASSERTION(result, "must not be null");
 
-  nsCAutoString path = GetAboutModuleName(aURI);
+  nsAutoCString path = GetAboutModuleName(aURI);
 
   nsresult rv;
   nsCOMPtr<nsIIOService> ioService = do_GetIOService(&rv);
   NS_ENSURE_SUCCESS(rv, rv);
 
   for (int i = 0; i < kRedirTotal; i++) {
     if (!strcmp(path.get(), kRedirMap[i].id)) {
       nsCOMPtr<nsIChannel> tempChannel;
@@ -136,17 +136,17 @@ AboutRedirector::NewChannel(nsIURI *aURI
   return NS_ERROR_ILLEGAL_VALUE;
 }
 
 NS_IMETHODIMP
 AboutRedirector::GetURIFlags(nsIURI *aURI, uint32_t *result)
 {
   NS_ENSURE_ARG_POINTER(aURI);
 
-  nsCAutoString name = GetAboutModuleName(aURI);
+  nsAutoCString name = GetAboutModuleName(aURI);
 
   for (int i = 0; i < kRedirTotal; i++) {
     if (name.Equals(kRedirMap[i].id)) {
       *result = kRedirMap[i].flags;
       return NS_OK;
     }
   }
 

--- a/browser/components/feeds/src/nsFeedSniffer.cpp
+++ b/browser/components/feeds/src/nsFeedSniffer.cpp
@@ -50,17 +50,17 @@ nsFeedSniffer::ConvertEncodedData(nsIReq
 {
   nsresult rv = NS_OK;
 
  mDecodedData = "";
  nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(request));
   if (!httpChannel)
     return NS_ERROR_NO_INTERFACE;
 
-  nsCAutoString contentEncoding;
+  nsAutoCString contentEncoding;
   httpChannel->GetResponseHeader(NS_LITERAL_CSTRING("Content-Encoding"), 
                                  contentEncoding);
   if (!contentEncoding.IsEmpty()) {
     nsCOMPtr<nsIStreamConverterService> converterService(do_GetService(NS_STREAMCONVERTERSERVICE_CONTRACTID));
     if (converterService) {
       ToLowerCase(contentEncoding);
 
       nsCOMPtr<nsIStreamListener> converter;
@@ -200,54 +200,54 @@ nsFeedSniffer::GetMIMETypeFromContent(ns
                                       uint32_t length, 
                                       nsACString& sniffedType)
 {
   nsCOMPtr<nsIHttpChannel> channel(do_QueryInterface(request));
   if (!channel)
     return NS_ERROR_NO_INTERFACE;
 
   // Check that this is a GET request, since you can't subscribe to a POST...
-  nsCAutoString method;
+  nsAutoCString method;
   channel->GetRequestMethod(method);
   if (!method.Equals("GET")) {
     sniffedType.Truncate();
     return NS_OK;
   }
 
   // We need to find out if this is a load of a view-source document. In this
   // case we do not want to override the content type, since the source display
   // does not need to be converted from feed format to XUL. More importantly, 
   // we don't want to change the content type from something 
   // nsContentDLF::CreateInstance knows about (e.g. application/xml, text/html 
   // etc) to something that only the application fe knows about (maybe.feed) 
   // thus deactivating syntax highlighting.
   nsCOMPtr<nsIURI> originalURI;
   channel->GetOriginalURI(getter_AddRefs(originalURI));
 
-  nsCAutoString scheme;
+  nsAutoCString scheme;
   originalURI->GetScheme(scheme);
   if (scheme.EqualsLiteral("view-source")) {
     sniffedType.Truncate();
     return NS_OK;
   }
 
   // Check the Content-Type to see if it is set correctly. If it is set to 
   // something specific that we think is a reliable indication of a feed, don't
   // bother sniffing since we assume the site maintainer knows what they're 
   // doing. 
-  nsCAutoString contentType;
+  nsAutoCString contentType;
   channel->GetContentType(contentType);
   bool noSniff = contentType.EqualsLiteral(TYPE_RSS) ||
                    contentType.EqualsLiteral(TYPE_ATOM);
 
   // Check to see if this was a feed request from the location bar or from
   // the feed: protocol. This is also a reliable indication.
   // The value of the header doesn't matter.  
   if (!noSniff) {
-    nsCAutoString sniffHeader;
+    nsAutoCString sniffHeader;
     nsresult foundHeader =
       channel->GetRequestHeader(NS_LITERAL_CSTRING("X-Moz-Is-Feed"),
                                 sniffHeader);
     noSniff = NS_SUCCEEDED(foundHeader);
   }
 
   if (noSniff) {
     // check for an attachment after we have a likely feed.

--- a/browser/components/shell/src/nsGNOMEShellService.cpp
+++ b/browser/components/shell/src/nsGNOMEShellService.cpp
@@ -174,17 +174,17 @@ nsGNOMEShellService::KeyMatchesAppName(c
   return matches;
 }
 
 bool
 nsGNOMEShellService::CheckHandlerMatchesAppName(const nsACString &handler) const
 {
   gint argc;
   gchar **argv;
-  nsCAutoString command(handler);
+  nsAutoCString command(handler);
 
   // The string will be something of the form: [/path/to/]browser "%s"
   // We want to remove all of the parameters and get just the binary name.
 
   if (g_shell_parse_argv(command.get(), &argc, &argv, NULL) && argc > 0) {
     command.Assign(argv[0]);
     g_strfreev(argv);
   }
@@ -202,17 +202,17 @@ nsGNOMEShellService::IsDefaultBrowser(bo
   *aIsDefaultBrowser = false;
   if (aStartupCheck)
     mCheckedThisSession = true;
 
   nsCOMPtr<nsIGConfService> gconf = do_GetService(NS_GCONFSERVICE_CONTRACTID);
   nsCOMPtr<nsIGIOService> giovfs = do_GetService(NS_GIOSERVICE_CONTRACTID);
 
   bool enabled;
-  nsCAutoString handler;
+  nsAutoCString handler;
   nsCOMPtr<nsIGIOMimeApp> gioApp;
 
   for (unsigned int i = 0; i < ArrayLength(appProtocols); ++i) {
     if (!appProtocols[i].essential)
       continue;
 
     if (gconf) {
       handler.Truncate();
@@ -249,17 +249,17 @@ nsGNOMEShellService::SetDefaultBrowser(b
 #ifdef DEBUG
   if (aForAllUsers)
     NS_WARNING("Setting the default browser for all users is not yet supported");
 #endif
 
   nsCOMPtr<nsIGConfService> gconf = do_GetService(NS_GCONFSERVICE_CONTRACTID);
   nsCOMPtr<nsIGIOService> giovfs = do_GetService(NS_GIOSERVICE_CONTRACTID);
   if (gconf) {
-    nsCAutoString appKeyValue;
+    nsAutoCString appKeyValue;
     if (mAppIsInPath) {
       // mAppPath is in the users path, so use only the basename as the launcher
       gchar *tmp = g_path_get_basename(mAppPath.get());
       appKeyValue = tmp;
       g_free(tmp);
     } else {
       appKeyValue = mAppPath;
     }
@@ -401,30 +401,30 @@ nsGNOMEShellService::SetDesktopBackgroun
   rv = imageContent->GetRequest(nsIImageLoadingContent::CURRENT_REQUEST,
                                 getter_AddRefs(request));
   if (!request) return rv;
   nsCOMPtr<imgIContainer> container;
   rv = request->GetImage(getter_AddRefs(container));
   if (!container) return rv;
 
   // Set desktop wallpaper filling style
-  nsCAutoString options;
+  nsAutoCString options;
   if (aPosition == BACKGROUND_TILE)
     options.Assign("wallpaper");
   else if (aPosition == BACKGROUND_STRETCH)
     options.Assign("stretched");
   else if (aPosition == BACKGROUND_FILL)
     options.Assign("zoom");
   else if (aPosition == BACKGROUND_FIT)
     options.Assign("scaled");
   else
     options.Assign("centered");
 
   // Write the background file to the home directory.
-  nsCAutoString filePath(PR_GetEnv("HOME"));
+  nsAutoCString filePath(PR_GetEnv("HOME"));
 
   // get the product brand name from localized strings
   nsString brandName;
   nsCID bundleCID = NS_STRINGBUNDLESERVICE_CID;
   nsCOMPtr<nsIStringBundleService> bundleService(do_GetService(bundleCID));
   if (bundleService) {
     nsCOMPtr<nsIStringBundle> brandBundle;
     rv = bundleService->CreateBundle(BRAND_PROPERTIES,
@@ -494,17 +494,17 @@ nsGNOMEShellService::SetDesktopBackgroun
 #define COLOR_8_TO_16_BIT(_c) ((_c) << 8 | (_c))
 
 NS_IMETHODIMP
 nsGNOMEShellService::GetDesktopBackgroundColor(uint32_t *aColor)
 {
   nsCOMPtr<nsIGSettingsService> gsettings = 
     do_GetService(NS_GSETTINGSSERVICE_CONTRACTID);
   nsCOMPtr<nsIGSettingsCollection> background_settings;
-  nsCAutoString background;
+  nsAutoCString background;
 
   if (gsettings) {
     gsettings->GetCollectionForSchema(
       NS_LITERAL_CSTRING(kDesktopBGSchema), getter_AddRefs(background_settings));
     if (background_settings) {
       background_settings->GetString(NS_LITERAL_CSTRING(kDesktopColorGSKey),
                                      background);
     }
@@ -546,17 +546,17 @@ ColorToCString(uint32_t aColor, nsCStrin
 
   PR_snprintf(buf, 14, "#%04x%04x%04x", red, green, blue);
 }
 
 NS_IMETHODIMP
 nsGNOMEShellService::SetDesktopBackgroundColor(uint32_t aColor)
 {
   NS_ASSERTION(aColor <= 0xffffff, "aColor has extra bits");
-  nsCAutoString colorString;
+  nsAutoCString colorString;
   ColorToCString(aColor, colorString);
 
   nsCOMPtr<nsIGSettingsService> gsettings =
     do_GetService(NS_GSETTINGSSERVICE_CONTRACTID);
   if (gsettings) {
     nsCOMPtr<nsIGSettingsCollection> background_settings;
     gsettings->GetCollectionForSchema(
       NS_LITERAL_CSTRING(kDesktopBGSchema), getter_AddRefs(background_settings));
@@ -574,17 +574,17 @@ nsGNOMEShellService::SetDesktopBackgroun
   }
 
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsGNOMEShellService::OpenApplication(int32_t aApplication)
 {
-  nsCAutoString scheme;
+  nsAutoCString scheme;
   if (aApplication == APPLICATION_MAIL)
     scheme.Assign("mailto");
   else if (aApplication == APPLICATION_NEWS)
     scheme.Assign("news");
   else
     return NS_ERROR_NOT_AVAILABLE;
 
   nsCOMPtr<nsIGIOService> giovfs = do_GetService(NS_GIOSERVICE_CONTRACTID);
@@ -595,17 +595,17 @@ nsGNOMEShellService::OpenApplication(int
       return gioApp->Launch(EmptyCString());
   }
 
   nsCOMPtr<nsIGConfService> gconf = do_GetService(NS_GCONFSERVICE_CONTRACTID);
   if (!gconf)
     return NS_ERROR_FAILURE;
 
   bool enabled;
-  nsCAutoString appCommand;
+  nsAutoCString appCommand;
   gconf->GetAppForProtocol(scheme, &enabled, appCommand);
 
   if (!enabled)
     return NS_ERROR_FAILURE;
 
   // XXX we don't currently handle launching a terminal window.
   // If the handler requires a terminal, bail.
   bool requiresTerminal;

--- a/browser/components/shell/src/nsMacShellService.cpp
+++ b/browser/components/shell/src/nsMacShellService.cpp
@@ -155,17 +155,17 @@ nsMacShellService::SetDesktopBackground(
   // Get the desired image file name
   nsCOMPtr<nsIURL> imageURL(do_QueryInterface(imageURI));
   if (!imageURL) {
     // XXXmano (bug 300293): Non-URL images (e.g. the data: protocol) are not
     // yet supported. What filename should we take here?
     return NS_ERROR_NOT_IMPLEMENTED;
   }
 
-  nsCAutoString fileName;
+  nsAutoCString fileName;
   imageURL->GetFileName(fileName);
   nsCOMPtr<nsIProperties> fileLocator
     (do_GetService("@mozilla.org/file/directory_service;1", &rv));
   NS_ENSURE_SUCCESS(rv, rv);
 
   // Get the current user's "Pictures" folder (That's ~/Pictures):
   fileLocator->Get(NS_OSX_PICTURE_DOCUMENTS_DIR, NS_GET_IID(nsIFile),
                    getter_AddRefs(mBackgroundFile));
@@ -242,17 +242,17 @@ nsMacShellService::OnStateChange(nsIWebP
     if (os)
       os->NotifyObservers(nullptr, "shell:desktop-background-changed", nullptr);
 
     bool exists = false;
     mBackgroundFile->Exists(&exists);
     if (!exists)
       return NS_OK;
 
-    nsCAutoString nativePath;
+    nsAutoCString nativePath;
     mBackgroundFile->GetNativePath(nativePath);
 
     AEDesc tAEDesc = { typeNull, nil };
     OSErr err = noErr;
     AliasHandle aliasHandle = nil;
     FSRef pictureRef;
     OSStatus status;