Use Skia's matchFamilyStyleCharacter API for font fallback

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

 /*
  * Copyright (C) 2006, 2007 Apple Computer, Inc.
  * Copyright (c) 2006, 2007, 2008, 2009, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 15 matching lines @@
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "platform/fonts/FontCache.h"
 
 #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"
 #include "platform/fonts/FontPlatformData.h"
 #include "platform/fonts/SimpleFontData.h"
 #include "platform/fonts/win/FontFallbackWin.h"
 
 namespace blink {
 
 HashMap<String, RefPtr<SkTypeface>>* FontCache::s_sideloadedFonts = 0;
@@ skipping 86 matching lines @@
         fontDescription.script(),
         fontDescription.locale(),
         &script,
         m_fontManager.get());
     FontPlatformData* data = 0;
     if (family) {
         FontFaceCreationParams createByFamily(AtomicString(family, wcslen(family)));
         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.
     // Make sure that all of them are lowercased.
     const static wchar_t* const cjkFonts[] = {
         L"arial unicode ms",
         L"ms pgothic",
         L"simsun",
         L"gulim",
         L"pmingliu",
@@ skipping 267 matching lines @@
         if (typefacesMatchesFamily(tf.get(), family)) {
             result->setMinSizeForSubpixel(minSizeForSubpixelForFont);
             break;
         }
     }
 
     return result.release();
 }
 
 } // namespace blink