Check for Unicode in Font before ICU call

Source/platform/fonts/shaping/HarfBuzzShaper.cpp

Index: Source/platform/fonts/shaping/HarfBuzzShaper.cpp
diff --git a/Source/platform/fonts/shaping/HarfBuzzShaper.cpp b/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
index a90b9252c8752960a9b220d2bf0cb1a36bc95377..41edd0ad321964cad35a903bdd3bf3d00d594d9a 100644
--- a/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
+++ b/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
@@ -359,6 +359,29 @@ static void normalizeCharacters(const TextRun& run, unsigned length, UChar* dest
         source = run.characters16();
     }
 
+    // Convert to NFC form if the text has diacritical marks.
+    icu::UnicodeString normalizedString;
+    UErrorCode errorICU = U_ZERO_ERROR;
+
+    for (unsigned i = 0; i < (unsigned)run.length(); ++i) {

[eae, 2015/02/10 15:40:12]

Here and elsewhere, use static_cast instead of C-style casts.

[h.joshi, 2015/02/17 03:44:47]

Done.

+        UChar ch = source[i];

[eae, 2015/02/10 15:40:12]

Only used once, no need for local variable.

[h.joshi, 2015/02/17 03:44:47]

Done.

+        if (::ublock_getCode(ch) == UBLOCK_COMBINING_DIACRITICAL_MARKS) {
+            icu::Normalizer::normalize(icu::UnicodeString(source,
+                run.length()), UNORM_NFC, 0 /* no options */,
+                normalizedString, errorICU);
+            if (U_FAILURE(errorICU))
+                normalizedString.remove();
+            break;
+        }
+    }
+
+    if (normalizedString.isEmpty()) {
+        length = (unsigned)run.length();
+    } else {
+        length = (unsigned)normalizedString.length();
+        source = normalizedString.getBuffer();
+    }
+
     *destinationLength = 0;
     while (position < length) {
         UChar32 character;
@@ -564,12 +587,21 @@ static inline int handleMultipleUChar(
     const UChar* markCharactersEnd,
     const UChar* normalizedBufferEnd)
 {
+    ASSERT(currentFontData);
     if (U_GET_GC_MASK(character) & U_GC_M_MASK) {
+        /* If current font does not have Unicode, we should not go further.
+            Blink will fallback to some other font to display this Unicode.
+        */
+        if (!currentFontData->fontHasGlyphForCharacter(character))
+            return 0;
+
         int markLength = clusterLength;
         while (markCharactersEnd < normalizedBufferEnd) {
             UChar32 nextCharacter;
             int nextCharacterLength = 0;
             U16_NEXT(markCharactersEnd, nextCharacterLength, normalizedBufferEnd - markCharactersEnd, nextCharacter);
+            if (!currentFontData->fontHasGlyphForCharacter(nextCharacter))
+                return 0;
             if (!(U_GET_GC_MASK(nextCharacter) & U_GC_M_MASK))
                 break;
             markLength += nextCharacterLength;