Bug 1211867 - Use the font's NBSP glyph (if present) rather than rendering NBSP using the standard <space> glyph. r=jdaggett

gfx/thebes/gfxFont.cpp

@@ -2343,10 +2343,15 @@ gfxFont::NotifyGlyphsChanged()
     }
 }
 
-static bool
+// If aChar is a "word boundary" for shaped-word caching purposes, return it;
+// else return 0.
+static char16_t
 IsBoundarySpace(char16_t aChar, char16_t aNextChar)
 {
-    return (aChar == ' ' || aChar == 0x00A0) && !IsClusterExtender(aNextChar);
+    if ((aChar == ' ' || aChar == 0x00A0) && !IsClusterExtender(aNextChar)) {
+        return aChar;
+    }
+    return 0;
 }
 
 #ifdef __GNUC__
@@ -2765,7 +2770,7 @@ gfxFont::SplitAndInitTextRun(gfxContext *aContext,
     for (uint32_t i = 0; i <= aRunLength; ++i) {
         T ch = nextCh;
         nextCh = (i < aRunLength - 1) ? aString[i + 1] : '\n';
-        bool boundary = IsBoundarySpace(ch, nextCh);
+        T boundary = IsBoundarySpace(ch, nextCh);
         bool invalid = !boundary && gfxFontGroup::IsInvalidChar(ch);
         uint32_t length = i - wordStart;
 
@@ -2827,16 +2832,19 @@ gfxFont::SplitAndInitTextRun(gfxContext *aContext,
                     gfxTextRunFactory::TEXT_ORIENT_VERTICAL_UPRIGHT :
                     gfxTextRunFactory::TEXT_ORIENT_VERTICAL_SIDEWAYS_RIGHT;
             }
-            if (!aTextRun->SetSpaceGlyphIfSimple(this, aContext,
+            if (boundary != ' ' ||
+                !aTextRun->SetSpaceGlyphIfSimple(this, aContext,
                                                  aRunStart + i, ch,
-                                                 orientation))
-            {
-                static const uint8_t space = ' ';
+                                                 orientation)) {
+                // Currently, the only "boundary" characters we recognize are
+                // space and no-break space, which are both 8-bit, so we force
+                // that flag (below). If we ever change IsBoundarySpace, we
+                // may need to revise this.
+                NS_ASSERTION(uint32_t(boundary) < 256, "unexpected boundary!");
                 gfxShapedWord *sw =
-                    GetShapedWord(aContext,
-                                  &space, 1,
-                                  gfxShapedWord::HashMix(0, ' '), aRunScript, aVertical,
-                                  appUnitsPerDevUnit,
+                    GetShapedWord(aContext, &boundary, 1,
+                                  gfxShapedWord::HashMix(0, boundary),
+                                  aRunScript, aVertical, appUnitsPerDevUnit,
                                   flags | gfxTextRunFactory::TEXT_IS_8BIT, tp);
                 if (sw) {
                     aTextRun->CopyGlyphDataFrom(sw, aRunStart + i);