Revert of Change fallback font collection in HarfBuzzShaper

Source/platform/fonts/shaping/CachingWordShapeIterator.h

Index: Source/platform/fonts/shaping/CachingWordShapeIterator.h
diff --git a/Source/platform/fonts/shaping/CachingWordShapeIterator.h b/Source/platform/fonts/shaping/CachingWordShapeIterator.h
index 526c7e397483827ef471c7de46bed6ec12342215..e004766e5a721191ff7c02ed99683d620eb8d260 100644
--- a/Source/platform/fonts/shaping/CachingWordShapeIterator.h
+++ b/Source/platform/fonts/shaping/CachingWordShapeIterator.h
@@ -36,9 +36,10 @@
 
 class CachingWordShapeIterator {
 public:
-    CachingWordShapeIterator(ShapeCache* cache, const TextRun& run
-        , const Font* font)
-        : m_shapeCache(cache), m_textRun(run), m_font(font), m_startIndex(0)
+    CachingWordShapeIterator(ShapeCache* cache, const TextRun& run,
+        const Font* font, HashSet<const SimpleFontData*>* fallbackFonts)
+        : m_shapeCache(cache), m_textRun(run), m_font(font)
+        , m_fallbackFonts(fallbackFonts), m_startIndex(0)
     {
         ASSERT(font);
         const FontDescription& fontDescription = font->fontDescription();
@@ -62,7 +63,7 @@
         if (!m_shapeByWord) {
             if (m_startIndex)
                 return false;
-            *wordResult = shapeWord(m_textRun, m_font);
+            *wordResult = shapeWord(m_textRun, m_font, m_fallbackFonts);
             m_startIndex = 1;
             return *wordResult;
         }
@@ -71,7 +72,7 @@
         if (m_startIndex < length) {
             if (m_textRun[m_startIndex] == spaceCharacter) {
                 TextRun wordRun = m_textRun.subRun(m_startIndex, 1);
-                *wordResult = shapeWord(wordRun, m_font);
+                *wordResult = shapeWord(wordRun, m_font, m_fallbackFonts);
                 m_startIndex++;
                 return true;
             }
@@ -80,7 +81,7 @@
                 if (i == length || m_textRun[i] == spaceCharacter) {
                     TextRun wordRun = m_textRun.subRun(m_startIndex,
                         i - m_startIndex);
-                    *wordResult = shapeWord(wordRun, m_font);
+                    *wordResult = shapeWord(wordRun, m_font, m_fallbackFonts);
                     m_startIndex = i;
                     return true;
                 }
@@ -90,15 +91,31 @@
     }
 
 private:
-    PassRefPtr<ShapeResult> shapeWord(const TextRun& wordRun, const Font* font)
+    void setFallbackFonts(const ShapeResult* wordResult,
+        HashSet<const SimpleFontData*>* fallbackFonts)
+    {
+        if (fallbackFonts) {
+            const HashSet<const SimpleFontData*>* fontsForWord =
+                wordResult->fallbackFonts();
+            HashSet<const SimpleFontData*>::const_iterator it;
+            for (it = fontsForWord->begin(); it != fontsForWord->end(); ++it)
+                fallbackFonts->add(*it);
+        }
+    }
+
+    PassRefPtr<ShapeResult> shapeWord(const TextRun& wordRun,
+        const Font* font, HashSet<const SimpleFontData*>* fallbackFonts)
     {
         ShapeCacheEntry* cacheEntry = m_wordResultCachable
             ? m_shapeCache->add(wordRun, ShapeCacheEntry())
             : nullptr;
-        if (cacheEntry && cacheEntry->m_shapeResult)
+        if (cacheEntry && cacheEntry->m_shapeResult) {
+            setFallbackFonts(cacheEntry->m_shapeResult.get(), fallbackFonts);
             return cacheEntry->m_shapeResult;
+        }
 
-        HarfBuzzShaper shaper(font, wordRun);
+        HashSet<const SimpleFontData*> fallbackFontsForWord;
+        HarfBuzzShaper shaper(font, wordRun, &fallbackFontsForWord);
         RefPtr<ShapeResult> shapeResult = shaper.shapeResult();
         if (!shapeResult)
             return nullptr;
@@ -106,12 +123,14 @@
         if (cacheEntry)
             cacheEntry->m_shapeResult = shapeResult;
 
+        setFallbackFonts(shapeResult.get(), fallbackFonts);
         return shapeResult.release();
     }
 
     ShapeCache* m_shapeCache;
     const TextRun& m_textRun;
     const Font* m_font;
+    HashSet<const SimpleFontData*>* m_fallbackFonts;
     unsigned m_startIndex : 30;
     unsigned m_wordResultCachable : 1;
     unsigned m_shapeByWord : 1;