Add support for shaper-driven line breaking to HarfBuzzShaper

third_party/WebKit/Source/platform/fonts/shaping/ShapeResult.cpp

 /*
  * Copyright (c) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 BlackBerry Limited. 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 399 matching lines @@
         m_runs.insert(pos, std::move(run));
         break;
       }
     }
   }
   // If we didn't find an existing slot to place it, append.
   if (run)
     m_runs.push_back(std::move(run));
 }
 
+void ShapeResult::copyRange(unsigned startOffset,
+                            unsigned endOffset,
+                            ShapeResult* target) const {
+  unsigned index = target->m_numCharacters;
+  for (const auto& run : m_runs) {
+    unsigned runStart = (*run).m_startIndex;
+    unsigned runEnd = runStart + (*run).m_numCharacters;
+
+    if (startOffset < runEnd && endOffset > runStart) {
+      unsigned start = startOffset > runStart ? startOffset - runStart : 0;
+      unsigned end = std::min(endOffset - runStart, runEnd);
+      DCHECK(end > start);
+
+      ShapeResult::RunInfo* subRun = (*run).createSubRun(start, end);
+      subRun->m_startIndex = index;
+      target->m_runs.push_back(WTF::wrapUnique(subRun));
+      target->m_width += subRun->m_width;
+      index += subRun->m_numCharacters;
+    }
+  }
+
+  target->m_numCharacters = index;
+}
+
 PassRefPtr<ShapeResult> ShapeResult::createForTabulationCharacters(
     const Font* font,
     const TextRun& textRun,
     float positionOffset,
     unsigned count) {
   const SimpleFontData* fontData = font->primaryFont();
   // Tab characters are always LTR or RTL, not TTB, even when
   // isVerticalAnyUpright().
   std::unique_ptr<ShapeResult::RunInfo> run =
       WTF::wrapUnique(new ShapeResult::RunInfo(
@@ skipping 14 matching lines @@
   result->m_width = run->m_width;
   result->m_numGlyphs = count;
   DCHECK_EQ(result->m_numGlyphs, count);  // no overflow
   result->m_hasVerticalOffsets =
       fontData->platformData().isVerticalAnyUpright();
   result->m_runs.push_back(std::move(run));
   return result.release();
 }
 
 }  // namespace blink