Rendering text-justify:distribute for 8 bit characters.

Source/platform/fonts/WidthIterator.cpp

Index: Source/platform/fonts/WidthIterator.cpp
diff --git a/Source/platform/fonts/WidthIterator.cpp b/Source/platform/fonts/WidthIterator.cpp
index b41624a7c49a8301b31c65f4ba96e19e08fc8732..1395deff111b763a0fc9bb36632e0ebcd8f3ba57 100644
--- a/Source/platform/fonts/WidthIterator.cpp
+++ b/Source/platform/fonts/WidthIterator.cpp
@@ -59,7 +59,7 @@ WidthIterator::WidthIterator(const Font* font, const TextRun& run, HashSet<const
         m_expansionPerOpportunity = 0;
     else {
         bool isAfterExpansion = m_isAfterExpansion;
-        unsigned expansionOpportunityCount = m_run.is8Bit() ? Character::expansionOpportunityCount(m_run.characters8(), m_run.length(), m_run.direction(), isAfterExpansion) : Character::expansionOpportunityCount(m_run.characters16(), m_run.length(), m_run.direction(), isAfterExpansion);
+        unsigned expansionOpportunityCount = m_run.is8Bit() ? Character::expansionOpportunityCount(m_run.characters8(), m_run.length(), m_run.direction(), isAfterExpansion, m_run.textJustify()) : Character::expansionOpportunityCount(m_run.characters16(), m_run.length(), m_run.direction(), isAfterExpansion, m_run.textJustify());
         if (isAfterExpansion && !m_run.allowsTrailingExpansion())
             expansionOpportunityCount--;
 
@@ -128,11 +128,12 @@ float WidthIterator::adjustSpacing(float width, const CharacterData& charData,
         width += m_font->fontDescription().letterSpacing();
 
     static bool expandAroundIdeographs = FontPlatformFeatures::canExpandAroundIdeographsInComplexText();
-    bool treatAsSpace = Character::treatAsSpace(charData.character);
-    if (treatAsSpace || (expandAroundIdeographs && Character::isCJKIdeographOrSymbol(charData.character))) {
+    bool isExpansionOpportunity = Character::treatAsSpace(charData.character) || (m_run.textJustify() == JustifyDistribute);
+    if (isExpansionOpportunity || (expandAroundIdeographs && Character::isCJKIdeographOrSymbol(charData.character))) {
+
         // Distribute the run's total expansion evenly over all expansion opportunities in the run.
         if (m_expansion) {
-            if (!treatAsSpace && !m_isAfterExpansion) {
+            if (!isExpansionOpportunity && !m_isAfterExpansion) {
                 // Take the expansion opportunity before this ideograph.
                 m_expansion -= m_expansionPerOpportunity;
                 float expansionAtThisOpportunity = m_expansionPerOpportunity;
@@ -161,7 +162,7 @@ float WidthIterator::adjustSpacing(float width, const CharacterData& charData,
 
         // Account for word spacing.
         // We apply additional space between "words" by adding width to the space character.
-        if (treatAsSpace && (charData.character != '\t' || !m_run.allowTabs())
+        if (isExpansionOpportunity && (charData.character != '\t' || !m_run.allowTabs())
             && (charData.characterOffset || charData.character == noBreakSpace)
             && m_font->fontDescription().wordSpacing()) {
             width += m_font->fontDescription().wordSpacing();