More LayoutLocale refactor with additional Chinese support

third_party/WebKit/Source/platform/fonts/skia/FontCacheSkia.cpp

 /*
  * Copyright (c) 2006, 2007, 2008, 2009 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 14 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 "SkFontMgr.h"
 #include "SkStream.h"
 #include "SkTypeface.h"
 #include "platform/Language.h"
-#include "platform/fonts/AcceptLanguagesResolver.h"
 #include "platform/fonts/AlternateFontFamily.h"
 #include "platform/fonts/FontCache.h"
 #include "platform/fonts/FontDescription.h"
 #include "platform/fonts/FontFaceCreationParams.h"
 #include "platform/fonts/SimpleFontData.h"
 #include "platform/graphics/skia/SkiaUtils.h"
 #include "public/platform/Platform.h"
 #include "public/platform/linux/WebSandboxSupport.h"
 #include "wtf/Assertions.h"
 #include "wtf/PtrUtil.h"
@@ skipping 28 matching lines @@
 // embedder has overriden the default fontManager with WebFontRendering::setSkiaFontMgr.
 // static
 AtomicString FontCache::getFamilyNameForCharacter(SkFontMgr* fm, UChar32 c, const FontDescription& fontDescription, FontFallbackPriority fallbackPriority)
 {
     ASSERT(fm);
 
     const size_t kMaxLocales = 4;
     const char* bcp47Locales[kMaxLocales];
     size_t localeCount = 0;
 
-    if (fallbackPriority == FontFallbackPriority::EmojiEmoji) {
+    // Fill in the list of locales in the reverse priority order.
+    // The last one is the highest.

[drott, 2016/07/28 08:05:23]

Perhaps we can rephrase this second line of the comment: Skia expects the
highest array index to be the first priority.

Makes sense to include this change.

Did you test this with mixed text-presentation and emoji-presentation pages on
Android?

[kojii, 2016/07/29 04:27:40]

Your text looks great, fixed. Wanted to put a link to Skia documents but it
looks like there doesn't exist...
Tested a few pages on a real device and see no differences.
http://unicode.org/emoji/charts/emoji-zwj-sequences.html
http://apps.timwhitlock.info/emoji/tables/unicode

I now remember we don't run most of LayoutTests on Android. Probably we should
have gtest or make a LayoutTest runnable on Linux that differentiate this line,
but I know it's a bit tricky to build such a test.

At least changing the order doesn't break major cases, and logically this is the
right fix, as we add content locale after the default locale.

+    const LayoutLocale* contentLocale = fontDescription.locale();
+    if (const LayoutLocale* hanLocale = LayoutLocale::localeForHan(contentLocale))
+        bcp47Locales[localeCount++] = hanLocale->localeForHanForSkFontMgr();
+    bcp47Locales[localeCount++] = LayoutLocale::getDefault().localeForSkFontMgr();
+    if (contentLocale)
+        bcp47Locales[localeCount++] = contentLocale->localeForSkFontMgr();
+    if (fallbackPriority == FontFallbackPriority::EmojiEmoji)
         bcp47Locales[localeCount++] = kAndroidColorEmojiLocale;
-    }
-    if (const char* hanLocale = AcceptLanguagesResolver::preferredHanSkFontMgrLocale())
-        bcp47Locales[localeCount++] = hanLocale;
-    bcp47Locales[localeCount++] = LayoutLocale::getDefault().localeForSkFontMgr().data();
-    if (const LayoutLocale* locale = fontDescription.locale())
-        bcp47Locales[localeCount++] = locale->localeForSkFontMgr().data();
     ASSERT_WITH_SECURITY_IMPLICATION(localeCount < kMaxLocales);
     RefPtr<SkTypeface> typeface = adoptRef(fm->matchFamilyStyleCharacter(0, SkFontStyle(), bcp47Locales, localeCount, c));
     if (!typeface)
         return emptyAtom;
 
     SkString skiaFamilyName;
     typeface->getFamilyName(&skiaFamilyName);
     return skiaFamilyName.c_str();
 }
 #endif
@@ skipping 108 matching lines @@
     return wrapUnique(new FontPlatformData(tf,
         name.data(),
         fontSize,
         (fontDescription.weight() > 200 + tf->fontStyle().weight()) || fontDescription.isSyntheticBold(),
         ((fontDescription.style() == FontStyleItalic || fontDescription.style() == FontStyleOblique) && !tf->isItalic()) || fontDescription.isSyntheticItalic(),
         fontDescription.orientation()));
 }
 #endif // !OS(WIN)
 
 } // namespace blink