Get additional DW font metrics when available.

src/ports/SkTypeface_win_dw.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkTypeface_win_dw_DEFINED
 #define SkTypeface_win_dw_DEFINED
 
 #include "SkAdvancedTypefaceMetrics.h"
 #include "SkDWrite.h"
 #include "SkHRESULT.h"
 #include "SkTScopedComPtr.h"
 #include "SkTypeface.h"
 #include "SkTypefaceCache.h"
 #include "SkTypes.h"
 
 #include <dwrite.h>
+#include <dwrite_1.h>
 
 class SkFontDescriptor;
 struct SkScalerContextRec;
 
 static SkTypeface::Style get_style(IDWriteFont* font) {
     int style = SkTypeface::kNormal;
     DWRITE_FONT_WEIGHT weight = font->GetWeight();
     if (DWRITE_FONT_WEIGHT_DEMI_BOLD <= weight) {
         style |= SkTypeface::kBold;
     }
@@ skipping 13 matching lines @@
                        IDWriteFontFamily* fontFamily,
                        IDWriteFontFileLoader* fontFileLoader = NULL,
                        IDWriteFontCollectionLoader* fontCollectionLoader = NULL)
         : SkTypeface(style, fontID, false)
         , fFactory(SkRefComPtr(factory))
         , fDWriteFontCollectionLoader(SkSafeRefComPtr(fontCollectionLoader))
         , fDWriteFontFileLoader(SkSafeRefComPtr(fontFileLoader))
         , fDWriteFontFamily(SkRefComPtr(fontFamily))
         , fDWriteFont(SkRefComPtr(font))
         , fDWriteFontFace(SkRefComPtr(fontFace))
-    { }
+    {
+        if (!SUCCEEDED(fDWriteFontFace->QueryInterface(&fDWriteFontFace1))) {
+            // IUnknown::QueryInterface states that if it fails, punk will be set to NULL.
+            // http://blogs.msdn.com/b/oldnewthing/archive/2004/03/26/96777.aspx
+            SK_ALWAYSBREAK(NULL == fDWriteFontFace1.get());
+        }
+    }
 
 public:
     SkTScopedComPtr<IDWriteFactory> fFactory;
     SkTScopedComPtr<IDWriteFontCollectionLoader> fDWriteFontCollectionLoader;
     SkTScopedComPtr<IDWriteFontFileLoader> fDWriteFontFileLoader;
     SkTScopedComPtr<IDWriteFontFamily> fDWriteFontFamily;
     SkTScopedComPtr<IDWriteFont> fDWriteFont;
     SkTScopedComPtr<IDWriteFontFace> fDWriteFontFace;
+    SkTScopedComPtr<IDWriteFontFace1> fDWriteFontFace1;
 
     static DWriteFontTypeface* Create(IDWriteFactory* factory,
                                       IDWriteFontFace* fontFace,
                                       IDWriteFont* font,
                                       IDWriteFontFamily* fontFamily,
                                       IDWriteFontFileLoader* fontFileLoader = NULL,
                                       IDWriteFontCollectionLoader* fontCollectionLoader = NULL) {
         SkTypeface::Style style = get_style(font);
         SkFontID fontID = SkTypefaceCache::NewFontID();
         return SkNEW_ARGS(DWriteFontTypeface, (style, fontID,
@@ skipping 28 matching lines @@
     virtual SkTypeface::LocalizedStrings* onCreateFamilyNameIterator() const SK_OVERRIDE;
     virtual int onGetTableTags(SkFontTableTag tags[]) const SK_OVERRIDE;
     virtual size_t onGetTableData(SkFontTableTag, size_t offset,
                                   size_t length, void* data) const SK_OVERRIDE;
 
 private:
     typedef SkTypeface INHERITED;
 };
 
 #endif