Update code to use helper function for better readability/searching.

Review URL: https://codereview.chromium.org/12834012

git-svn-id: http://skia.googlecode.com/svn/trunk@8287 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/ports/SkXMLParser_tinyxml.cpp b/src/ports/SkXMLParser_tinyxml.cpp
index f357592..5f9f3a6 100644
--- a/src/ports/SkXMLParser_tinyxml.cpp
+++ b/src/ports/SkXMLParser_tinyxml.cpp
@@ -58,7 +58,7 @@
 
 bool SkXMLParser::parse(SkStream& stream)
 {
-    size_t size = stream.read(NULL, 0);
+    size_t size = stream.getLength();
 
     SkAutoMalloc    buffer(size + 1);
     char*           buf = (char*)buffer.get();