Use Skia's matchFamilyStyleCharacter API for font fallback

third_party/WebKit/Source/platform/fonts/win/FontCacheSkiaWin.cpp

Index: third_party/WebKit/Source/platform/fonts/win/FontCacheSkiaWin.cpp
diff --git a/third_party/WebKit/Source/platform/fonts/win/FontCacheSkiaWin.cpp b/third_party/WebKit/Source/platform/fonts/win/FontCacheSkiaWin.cpp
index 5a61fc126196325097777b82e2cfa2d24a56a1ce..923e19fddbe07cd547b92a60befe520e159b398b 100644
--- a/third_party/WebKit/Source/platform/fonts/win/FontCacheSkiaWin.cpp
+++ b/third_party/WebKit/Source/platform/fonts/win/FontCacheSkiaWin.cpp
@@ -33,6 +33,7 @@
 
 #include "SkFontMgr.h"
 #include "SkTypeface_win.h"
+#include "platform/Language.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/fonts/FontDescription.h"
 #include "platform/fonts/FontFaceCreationParams.h"
@@ -139,6 +140,35 @@ PassRefPtr<SimpleFontData> FontCache::fallbackFontForCharacter(
         data = getFontPlatformData(fontDescription, createByFamily);
     }
 
+    if (!data || !data->fontContainsCharacter(character)) {
+        const char* bcp47Locale = nullptr;
+        int localeCount = 0;
+        CString fontLocale;
+        // If the font description has a locale, use that. Otherwise, Skia will fall back

[eae, 2016/02/29 23:11:26]

Wrap at 80 col, you'll probably do a better job of doing so then the pending
batch job.

[Ilya Kulshin, 2016/03/01 03:31:14]

Done.

+        // on the user's default locale.
+        // TODO(kulshin): extract locale fallback logic from FontCacheAndroid.cpp and share that code
+        if (!fontDescription.locale().isEmpty()) {
+            fontLocale = toSkFontMgrLocale(fontDescription.locale());
+            bcp47Locale = fontLocale.data();
+            localeCount = 1;

[eae, 2016/02/29 23:11:26]

This is set but never used. Please remove.

[Ilya Kulshin, 2016/03/01 03:31:14]

This is used in the call to matchFamilyStyleCharacter.

+        }
+
+        // LChar is unsigned, while matchFamilyStyleCharacter requires a plain char*.
+        const LChar* fontDescriptionFamilyName = fontDescription.family().family().characters8();
+        const char* skiaFamilyName = reinterpret_cast<const char*>(fontDescriptionFamilyName);

[eae, 2016/02/29 23:11:26]

Elsewhere we convert the family name to utf8 before passing it to Skia. 

Cstring familyName = fontDescription.family().family().utf8();
const char* skiaFamilyName = familyName.data();

[Ilya Kulshin, 2016/03/01 03:31:14]

Oh, not sure how I missed that API. That works much better, thanks for the tip!

+        static_assert(sizeof(*fontDescriptionFamilyName) == sizeof(*skiaFamilyName),
+            "skiaFamilyName and fontDescriptionFamilyName must be same size");
+
+        SkTypeface* typeface = m_fontManager->matchFamilyStyleCharacter(
+            skiaFamilyName, fontDescription.skiaFontStyle(), &bcp47Locale, localeCount, character);
+        if (typeface) {
+            SkString skiaFamily;
+            typeface->getFamilyName(&skiaFamily);
+            FontFaceCreationParams createByFamily(AtomicString(skiaFamily.c_str()));
+            data = getFontPlatformData(fontDescription, createByFamily);
+        }
+    }
+
     // Last resort font list : PanUnicode. CJK fonts have a pretty
     // large repertoire. Eventually, we need to scan all the fonts
     // on the system to have a Firefox-like coverage.