convert pdf design document to markdown

site/user/sample/pdf.md

Index: site/user/sample/pdf.md
diff --git a/site/user/sample/pdf.md b/site/user/sample/pdf.md
new file mode 100644
index 0000000000000000000000000000000000000000..efadd5b42a7d219479c3249b0ee779af3e3d72fc
--- /dev/null
+++ b/site/user/sample/pdf.md
@@ -0,0 +1,29 @@
+Using Skia's PDF Backend
+========================
+
+Here is an example of using Skia's PDF backend in the recommended way:
+via the SkDocument and SkCanvas APIs.
+
+<!--?prettify?-->
+
+    #include "SkDocument.h"
+
+    bool WritePDF() {
+        SkWStream* output = ....;
+
+        SkAutoTUnref<SkDocument> pdfDocument(
+                SkDocument::CreatePDF(outputStream));
+
+        int numberOfPages = ....;
+        for (int page = 0; page < numberOfPages; ++page) {
+            SkScalar pageWidth = ....;
+            SkScalar pageHeight = ....;
+            SkCanvas* pageCanvas =
+                    pdfDocument->beginPage(pageWidth, pageHeight);
+
+            // ....insert canvas draw commands here....
+
+            pdfDocument->endPage();
+        }
+        return pdfDocument->close();
+    }