pdf viewer: fix a few warnings, and enable warning as errors

experimental/PdfViewer/SkPdfFont.h

Index: experimental/PdfViewer/SkPdfFont.h
===================================================================
--- experimental/PdfViewer/SkPdfFont.h	(revision 9962)
+++ experimental/PdfViewer/SkPdfFont.h	(working copy)
@@ -20,11 +20,20 @@
 class SkPdfMultiMasterFont;
 class SkPdfFont;
 
-
 struct SkPdfStandardFontEntry {
+    // We don't own this pointer!
     const char* fName;
     bool fIsBold;
     bool fIsItalic;
+    SkPdfStandardFontEntry()
+    : fName(NULL),
+      fIsBold(false),
+      fIsItalic(false) {}
+
+    SkPdfStandardFontEntry(const char* name, bool bold, bool italic)
+        : fName(name),
+          fIsBold(bold),
+          fIsItalic(italic) {}
 };
 
 std::map<std::string, SkPdfStandardFontEntry>& getStandardFonts();