Implement charToGlyph on remaining ports.

src/ports/SkFontHost_win_dw.cpp

Index: src/ports/SkFontHost_win_dw.cpp
===================================================================
--- src/ports/SkFontHost_win_dw.cpp	(revision 10894)
+++ src/ports/SkFontHost_win_dw.cpp	(working copy)
@@ -554,6 +554,8 @@
                                 SkAdvancedTypefaceMetrics::PerGlyphInfo,
                                 const uint32_t*, uint32_t) const SK_OVERRIDE;
     virtual void onGetFontDescriptor(SkFontDescriptor*, bool*) const SK_OVERRIDE;
+    virtual int onCharsToGlyphs(const void* chars, Encoding encoding,
+                                uint16_t glyphs[], int glyphCount) const SK_OVERRIDE;
     virtual int onCountGlyphs() const SK_OVERRIDE;
     virtual int onGetUPEM() const SK_OVERRIDE;
     virtual SkTypeface::LocalizedStrings* onCreateFamilyNameIterator() const SK_OVERRIDE;
@@ -1123,6 +1125,61 @@
     *isLocalStream = SkToBool(fDWriteFontFileLoader.get());
 }
 
+static SkUnichar next_utf8(const void** chars) {
+    return SkUTF8_NextUnichar((const char**)chars);
+}
+
+static SkUnichar next_utf16(const void** chars) {
+    return SkUTF16_NextUnichar((const uint16_t**)chars);
+}
+
+static SkUnichar next_utf32(const void** chars) {
+    const SkUnichar** uniChars = (const SkUnichar**)chars;
+    SkUnichar uni = **uniChars;
+    *uniChars += 1;
+    return uni;
+}
+
+typedef SkUnichar (*EncodingProc)(const void**);
+
+static EncodingProc find_encoding_proc(SkTypeface::Encoding enc) {
+    static const EncodingProc gProcs[] = {
+        next_utf8, next_utf16, next_utf32
+    };
+    SkASSERT((size_t)enc < SK_ARRAY_COUNT(gProcs));
+    return gProcs[enc];
+}
+
+int DWriteFontTypeface::onCharsToGlyphs(const void* chars, Encoding encoding,
+                                        uint16_t glyphs[], int glyphCount) const
+{
+    EncodingProc next_uni_proc = find_encoding_proc(encoding);
+
+    if (NULL == glyphs) {
+        for (int i = 0; i < glyphCount; ++i) {
+            const SkUnichar c = next_uni_proc(&chars);
+            UINT16 glyphIndex;
+            fDWriteFontFace->GetGlyphIndices((UINT32*)&c, 1, &glyphIndex);
+            if (0 == glyphIndex) {
+                return i;
+            }
+        }
+        return glyphCount;
+    }
+
+    int first = glyphCount;
+    for (int i = 0; i < glyphCount; ++i) {
+        const SkUnichar c = next_uni_proc(&chars);
+        UINT16 glyphIndex;
+        fDWriteFontFace->GetGlyphIndices((UINT32*)&c, 1, &glyphIndex);
+        glyphs[i] = glyphIndex;
+        if (0 == glyphIndex && i < first) {
+            first = i;
+        }
+    }
+    return first;
+}
+
 int DWriteFontTypeface::onCountGlyphs() const {
     return fDWriteFontFace->GetGlyphCount();
 }