[PDF] Rewind the font stream if font subsetting fails.

R=edisonn@google.com

Review URL: https://codereview.chromium.org/23654012

git-svn-id: http://skia.googlecode.com/svn/trunk@11116 2bbb7eff-a529-9590-31e7-b0007b416f81

src/pdf/SkPDFFont.cpp

@@ -582,6 +582,7 @@ static int get_subset_font_stream(const char* fontName,
         *fontStream = subsetFontStream;
         return fontSize;
     }
+    fontData->rewind();
 #else
     sk_ignore_unused_variable(fontName);
     sk_ignore_unused_variable(subset);