Add a default-default font for DirectWrite.

src/ports/SkFontHost_win_dw.cpp

Index: src/ports/SkFontHost_win_dw.cpp
===================================================================
--- src/ports/SkFontHost_win_dw.cpp	(revision 13916)
+++ src/ports/SkFontHost_win_dw.cpp	(working copy)
@@ -1674,9 +1674,8 @@
 
     if (exists) {
         HR(fFontCollection->GetFontFamily(index, fontFamily));
-        return S_OK;
     }
-    return S_FALSE;
+    return S_OK;
 }
 
 HRESULT SkFontMgr_DirectWrite::getDefaultFontFamily(IDWriteFontFamily** fontFamily) const {
@@ -1690,7 +1689,6 @@
     }
     HRM(this->getByFamilyName(metrics.lfMessageFont.lfFaceName, fontFamily),
         "Could not create DWrite font family from LOGFONT.");
-
     return S_OK;
 }
 
@@ -1709,6 +1707,12 @@
         HRNM(this->getDefaultFontFamily(&fontFamily), "Could not get default font family.");
     }
 
+    if (NULL == fontFamily.get()) {
+        // Could not obtain the default font.
+        HRNM(fFontCollection->GetFontFamily(0, &fontFamily),
+             "Could not get default-default font family.");
+    }
+
     SkTScopedComPtr<IDWriteFont> font;
     DWRITE_FONT_WEIGHT weight = (styleBits & SkTypeface::kBold)
                               ? DWRITE_FONT_WEIGHT_BOLD