Check for Unicode in Font before ICU call

Source/platform/fonts/shaping/HarfBuzzShaper.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 341 matching lines @@
     bool error = false;
     const UChar* source;
     String stringFor8BitRun;
     if (run.is8Bit()) {
         stringFor8BitRun = String::make16BitFrom8BitSource(run.characters8(), run.length());
         source = stringFor8BitRun.characters16();
     } else {
         source = run.characters16();
     }
 
+    // Convert to NFC form if the text has diacritical marks. In most of the font, OTF rules
+    // for diacritical marks are missing. Using ICU calls to convert to final form and then pass
+    // updated Unicode string to Harfbuzz.
+    icu::UnicodeString normalizedString;
+    UErrorCode errorICU = U_ZERO_ERROR;
+    bool isDiacriticalMarkPresent = false;
+
     *destinationLength = 0;
     while (position < length) {
         UChar32 character;
         U16_NEXT(source, position, length, character);
         // Don't normalize tabs as they are not treated as spaces for word-end.
-        if (run.normalizeSpace() && Character::isNormalizedCanvasSpaceCharacter(character))
+        if (run.normalizeSpace() && Character::isNormalizedCanvasSpaceCharacter(character)) {
             character = spaceCharacter;
-        else if (Character::treatAsSpace(character) && character != tabulationCharacter)
+        } else if (Character::treatAsSpace(character) && character != tabulationCharacter) {
             character = spaceCharacter;
-        else if (Character::treatAsZeroWidthSpaceInComplexScript(character))
+        } else if (Character::treatAsZeroWidthSpaceInComplexScript(character)) {
             character = zeroWidthSpaceCharacter;
+        } else if (!isDiacriticalMarkPresent && ::ublock_getCode(character) == UBLOCK_COMBINING_DIACRITICAL_MARKS) {
+            isDiacriticalMarkPresent = true;
+            icu::Normalizer::normalize(icu::UnicodeString(source, length), UNORM_NFC, 0 , normalizedString, errorICU);
+            if (U_FAILURE(errorICU)) {
+                normalizedString.remove();
+            } else if (!normalizedString.isEmpty()) {
+                *destinationLength = 0;
+                position = 0;
+                length = static_cast<int>(normalizedString.length());
+                source = normalizedString.getBuffer();
+                continue;
+            }
+        }
 
         U16_APPEND(destination, *destinationLength, length, character, error);
         ASSERT_UNUSED(error, !error);
     }
 }
 
 HarfBuzzShaper::HarfBuzzShaper(const Font* font, const TextRun& run, const GlyphData* emphasisData,
     HashSet<const SimpleFontData*>* fallbackFonts, FloatRect* bounds)
     : Shaper(font, run, emphasisData, fallbackFonts, bounds)
     , m_normalizedBufferLength(0)
@@ skipping 824 matching lines @@
     // possibly invalid from, to arguments.
     if (!foundToX && !foundFromX)
         fromX = toX = 0;
 
     if (fromX < toX)
         return FloatRect(point.x() + fromX, point.y(), toX - fromX, height);
     return FloatRect(point.x() + toX, point.y(), fromX - toX, height);
 }
 
 } // namespace blink