Expose DocumentViewerImpl::CallChildren with an API that fills an array. (Bug 747231, patch 3) r=roc

--HG--
extra : transplant_source : %FFc%40%AE%D6%22%40%1D%7F%F7%A8%BC%1A%ECG%98G%DCFf

docshell/base/nsIMarkupDocumentViewer.idl

@@ -37,10 +37,6 @@
  *
  * ***** END LICENSE BLOCK ***** */
 
-/**
- * The nsIContentViewerEdit    
- */
-
 /**
  * The nsIMarkupDocumentViewer
  * This interface describes the properties of a content viewer 
@@ -51,8 +47,16 @@
 
 interface nsIDOMNode;
 
+%{C++
+#include "nsCOMPtr.h"
+#include "nsTArray.h"
+%}
 
-[scriptable, uuid(79286cd6-8293-4def-ba26-76422efc3d2a)]
+interface nsIMarkupDocumentViewer;
+
+[ref] native nsIMarkupDocumentViewerTArray(nsTArray<nsCOMPtr<nsIMarkupDocumentViewer> >);
+
+[scriptable, uuid(1016d5e8-690f-4d97-8ac5-d50ffa341c46)]
 interface nsIMarkupDocumentViewer : nsISupports
 {
 
@@ -150,4 +154,10 @@ interface nsIMarkupDocumentViewer : nsISupports
   /** The minimum font size  */
   attribute long minFontSize;
 
+  /**
+   * Append |this| and all of its descendants to the given array,
+   * in depth-first pre-order traversal.
+   */
+  [noscript] void appendSubtree(in nsIMarkupDocumentViewerTArray array);
+
 };

layout/base/nsDocumentViewer.cpp

@@ -3253,6 +3253,21 @@ NS_IMETHODIMP DocumentViewerImpl::GetBidiOptions(PRUint32* aBidiOptions)
   return NS_OK;
 }
 
+static void
+AppendChildSubtree(nsIMarkupDocumentViewer* aChild, void* aClosure)
+{
+  nsTArray<nsCOMPtr<nsIMarkupDocumentViewer> >& array =
+    *static_cast<nsTArray<nsCOMPtr<nsIMarkupDocumentViewer> >*>(aClosure);
+  aChild->AppendSubtree(array);
+}
+
+NS_IMETHODIMP DocumentViewerImpl::AppendSubtree(nsTArray<nsCOMPtr<nsIMarkupDocumentViewer> >& aArray)
+{
+  aArray.AppendElement(this);
+  CallChildren(AppendChildSubtree, &aArray);
+  return NS_OK;
+}
+
 NS_IMETHODIMP DocumentViewerImpl::SizeToContent()
 {
    NS_ENSURE_TRUE(mDocument, NS_ERROR_NOT_AVAILABLE);