diff --git a/gfx/thebes/public/gfxPangoFonts.h b/gfx/thebes/public/gfxPangoFonts.h
index ff86728d7db..970a26c1e6c 100644
--- a/gfx/thebes/public/gfxPangoFonts.h
+++ b/gfx/thebes/public/gfxPangoFonts.h
@@ -54,6 +54,7 @@
 // #define ENABLE_XFT_FAST_PATH_ALWAYS
 
 #include "nsDataHashtable.h"
+#include "nsClassHashtable.h"
 
 class FontSelector;
 
@@ -74,11 +75,13 @@ public:
 
     void GetMozLang(nsACString &aMozLang);
     void GetActualFontFamily(nsACString &aFamily);
-    PangoFont *GetPangoFont();
 
     XftFont *GetXftFont () { RealizeXftFont (); return mXftFont; }
+    PangoFont *GetPangoFont() { RealizePangoFont(); return mPangoFont; }
     gfxFloat GetAdjustedSize() { RealizeFont(); return mAdjustedSize; }
 
+    PRBool HasGlyph(const PRUint32 aChar);
+
     virtual gfxTextRun::Metrics Measure(gfxTextRun *aTextRun,
                                         PRUint32 aStart, PRUint32 aEnd,
                                         PRBool aTightBoundingBox,
@@ -91,6 +94,8 @@ protected:
     PangoContext *mPangoCtx;
 
     XftFont *mXftFont;
+    PangoFont *mPangoFont;
+    PangoFont *mGlyphTestingFont;
     cairo_scaled_font_t *mCairoFont;
 
     PRBool mHasMetrics;
@@ -100,6 +105,8 @@ protected:
     void RealizeFont(PRBool force = PR_FALSE);
     void RealizeXftFont(PRBool force = PR_FALSE);
     void GetSize(const char *aString, PRUint32 aLength, gfxSize& inkSize, gfxSize& logSize);
+    void RealizePangoFont(PRBool aForce = PR_FALSE);
+    void GetCharSize(const char aChar, gfxSize& aInkSize, gfxSize& aLogSize);
 
     virtual void SetupCairoFont(cairo_t *aCR);
 };
@@ -130,21 +137,17 @@ protected:
 
     // ****** Textrun glyph conversion helpers ******
 
-    // If aUTF16Text is null, then the string contains no characters >= 0x100
     void InitTextRun(gfxTextRun *aTextRun, const gchar *aUTF8Text,
-                     PRUint32 aUTF8Length, PRUint32 aUTF8HeaderLength,
-                     const PRUnichar *aUTF16Text, PRUint32 aUTF16Length);
+                     PRUint32 aUTF8Length, PRUint32 aUTF8HeaderLength);
     // Returns NS_ERROR_FAILURE if there's a missing glyph
     nsresult SetGlyphs(gfxTextRun *aTextRun, const gchar *aUTF8,
                        PRUint32 aUTF8Length,
                        PRUint32 *aUTF16Offset, PangoGlyphString *aGlyphs,
                        PangoGlyphUnit aOverrideSpaceWidth,
                        PRBool aAbortOnMissingGlyph);
-    // If aUTF16Text is null, then the string contains no characters >= 0x100.
-    // Returns NS_ERROR_FAILURE if we require the itemizing path
-    nsresult CreateGlyphRunsFast(gfxTextRun *aTextRun,
-                                 const gchar *aUTF8, PRUint32 aUTF8Length,
-                                 const PRUnichar *aUTF16Text, PRUint32 aUTF16Length);
+    nsresult SetMissingGlyphs(gfxTextRun *aTextRun,
+                              const gchar *aUTF8, PRUint32 aUTF8Length,
+                              PRUint32 *aUTF16Offset);
     void CreateGlyphRunsItemizing(gfxTextRun *aTextRun,
                                   const gchar *aUTF8, PRUint32 aUTF8Length,
                                   PRUint32 aUTF8HeaderLength);
@@ -161,4 +164,69 @@ private:
     nsTArray<gfxFontStyle> mAdditionalStyles;
 };
 
+class gfxPangoFontWrapper {
+public:
+    gfxPangoFontWrapper(PangoFont *aFont) {
+        mFont = aFont;
+        g_object_ref(mFont);
+    }
+    ~gfxPangoFontWrapper() {
+        if (mFont)
+            g_object_unref(mFont);
+    }
+    PangoFont* Get() { return mFont; }
+private:
+    PangoFont *mFont;
+};
+
+class gfxPangoFontCache
+{
+public:
+    gfxPangoFontCache();
+    ~gfxPangoFontCache();
+
+    static gfxPangoFontCache* GetPangoFontCache() {
+        if (!sPangoFontCache)
+            sPangoFontCache = new gfxPangoFontCache();
+        return sPangoFontCache;
+    }
+    static void Shutdown() {
+        if (sPangoFontCache)
+            delete sPangoFontCache;
+        sPangoFontCache = nsnull;
+    }
+
+    void Put(const PangoFontDescription *aFontDesc, PangoFont *aPangoFont);
+    PangoFont* Get(const PangoFontDescription *aFontDesc);
+private:
+    static gfxPangoFontCache *sPangoFontCache;
+    nsClassHashtable<nsUint32HashKey,  gfxPangoFontWrapper> mPangoFonts;
+};
+
+// XXX we should remove this class, because this class is used only in |HasGlyph| of gfxPangoFont.
+// But it can use fontconfig directly after bug 366664.
+class gfxPangoFontNameMap
+{
+public:
+    gfxPangoFontNameMap();
+    ~gfxPangoFontNameMap();
+
+    static gfxPangoFontNameMap* GetPangoFontNameMap() {
+        if (!sPangoFontNameMap)
+            sPangoFontNameMap = new gfxPangoFontNameMap();
+        return sPangoFontNameMap;
+    }
+    static void Shutdown() {
+        if (sPangoFontNameMap)
+            delete sPangoFontNameMap;
+        sPangoFontNameMap = nsnull;
+    }
+
+    void Put(const nsACString &aName, PangoFont *aPangoFont);
+    PangoFont* Get(const nsACString &aName);
+
+private:
+    static gfxPangoFontNameMap *sPangoFontNameMap;
+    nsClassHashtable<nsCStringHashKey, gfxPangoFontWrapper> mPangoFonts;
+};
 #endif /* GFX_PANGOFONTS_H */
diff --git a/gfx/thebes/src/gfxPangoFonts.cpp b/gfx/thebes/src/gfxPangoFonts.cpp
index 6af5f7c7916..15390c832ba 100644
--- a/gfx/thebes/src/gfxPangoFonts.cpp
+++ b/gfx/thebes/src/gfxPangoFonts.cpp
@@ -97,6 +97,9 @@
 static PangoLanguage *GetPangoLanguage(const nsACString& aLangGroup);
 static void GetMozLanguage(const PangoLanguage *aLang, nsACString &aMozLang);
 
+/* static */ gfxPangoFontCache* gfxPangoFontCache::sPangoFontCache = nsnull;
+/* static */ gfxPangoFontNameMap* gfxPangoFontNameMap::sPangoFontNameMap = nsnull;
+
 /**
  ** gfxPangoFontGroup
  **/
@@ -266,7 +269,8 @@ gfxPangoFont::gfxPangoFont(const nsAString &aName,
                            const gfxFontStyle *aFontStyle)
     : gfxFont(aName, aFontStyle),
     mPangoFontDesc(nsnull), mPangoCtx(nsnull),
-    mXftFont(nsnull), mCairoFont(nsnull), mHasMetrics(PR_FALSE),
+    mXftFont(nsnull), mPangoFont(nsnull), mGlyphTestingFont(nsnull),
+    mCairoFont(nsnull), mHasMetrics(PR_FALSE),
     mAdjustedSize(0)
 {
     InitPangoLib();
@@ -277,6 +281,12 @@ gfxPangoFont::~gfxPangoFont()
     if (mPangoCtx)
         g_object_unref(mPangoCtx);
 
+    if (mPangoFont)
+        g_object_unref(mPangoFont);
+
+    if (mGlyphTestingFont)
+        g_object_unref(mGlyphTestingFont);
+
     if (mPangoFontDesc)
         pango_font_description_free(mPangoFontDesc);
 
@@ -288,6 +298,8 @@ gfxPangoFont::~gfxPangoFont()
 gfxPangoFont::Shutdown()
 {
     ShutdownPangoLib();
+    gfxPangoFontCache::Shutdown();
+    gfxPangoFontNameMap::Shutdown();
 }
 
 static PangoStyle
@@ -364,6 +376,12 @@ gfxPangoFont::RealizeFont(PRBool force)
         g_object_unref(mPangoCtx);
     if (mPangoFontDesc)
         pango_font_description_free(mPangoFontDesc);
+    if (mPangoFont) {
+        g_object_unref(mPangoFont);
+        mPangoFont = nsnull;
+        mXftFont = nsnull;
+        // XXX we don't need to reset mGlyphTestingFont
+    }
 
     mPangoFontDesc = pango_font_description_new();
 
@@ -396,7 +414,7 @@ gfxPangoFont::RealizeFont(PRBool force)
         return;
 
     gfxSize isz, lsz;
-    GetSize("x", 1, isz, lsz);
+    GetCharSize('x', isz, lsz);
     gfxFloat aspect = isz.height / GetStyle()->size;
     mAdjustedSize =
         PR_MAX(NS_round(GetStyle()->size*(GetStyle()->sizeAdjust/aspect)), 1.0);
@@ -414,39 +432,69 @@ gfxPangoFont::RealizeXftFont(PRBool force)
         return;
     }
 
-    PangoFcFont *fcfont = PANGO_FC_FONT(GetPangoFont());
-    mXftFont = pango_xft_font_get_font(PANGO_FONT(fcfont));
+    mXftFont = pango_xft_font_get_font(GetPangoFont());
 }
 
 void
-gfxPangoFont::GetSize(const char *aCharString, PRUint32 aLength, gfxSize& inkSize, gfxSize& logSize)
+gfxPangoFont::RealizePangoFont(PRBool aForce)
 {
+    if (!aForce && mPangoFont)
+        return;
+    if (mPangoFont) {
+        g_object_unref(mPangoFont);
+        mPangoFont = nsnull;
+        mXftFont = nsnull;
+    }
     RealizeFont();
+    gfxPangoFontCache *cache = gfxPangoFontCache::GetPangoFontCache();
+    if (!cache)
+        return; // Error
+    mPangoFont = cache->Get(mPangoFontDesc);
+    if (mPangoFont)
+        return;
+    mPangoFont = pango_context_load_font(mPangoCtx, mPangoFontDesc);
+    if (!mPangoFont)
+        return; // Error
+    cache->Put(mPangoFontDesc, mPangoFont);
 
-    PangoAttrList *al = pango_attr_list_new();
-    GList *items = pango_itemize(mPangoCtx, aCharString, 0, aLength, al, NULL);
-    pango_attr_list_unref(al);
-
-    if (!items || g_list_length(items) != 1)
+    if (mGlyphTestingFont)
         return;
 
-    PangoItem *item = (PangoItem*) items->data;
+    // Append this to font name map
+    gfxPangoFontNameMap *fontNameMap = gfxPangoFontNameMap::GetPangoFontNameMap();
+    if (!fontNameMap)
+        return; // Error
+    NS_ConvertUTF16toUTF8 name(mName);
+    mGlyphTestingFont = fontNameMap->Get(name);
+    if (mGlyphTestingFont)
+        return;
+    fontNameMap->Put(name, mPangoFont);
+}
+
+void
+gfxPangoFont::GetCharSize(const char aChar, gfxSize& aInkSize, gfxSize& aLogSize)
+{
+    PangoAnalysis analysis;
+    analysis.font = GetPangoFont();
+    analysis.level = 0;
+    analysis.lang_engine = nsnull;
+    analysis.extra_attrs = nsnull;
+    analysis.language = pango_language_from_string("en");
+    analysis.shape_engine = pango_font_find_shaper(analysis.font, analysis.language, aChar);
 
     PangoGlyphString *glstr = pango_glyph_string_new();
-    pango_shape (aCharString, aLength, &(item->analysis), glstr);
+    pango_shape(&aChar, 1, &analysis, glstr);
 
     PangoRectangle ink_rect, log_rect;
-    pango_glyph_string_extents (glstr, item->analysis.font, &ink_rect, &log_rect);
+    pango_glyph_string_extents(glstr, analysis.font, &ink_rect, &log_rect);
 
-    inkSize.width = ink_rect.width / FLOAT_PANGO_SCALE;
-    inkSize.height = ink_rect.height / FLOAT_PANGO_SCALE;
+    aInkSize.width = ink_rect.width / FLOAT_PANGO_SCALE;
+    aInkSize.height = ink_rect.height / FLOAT_PANGO_SCALE;
 
-    logSize.width = log_rect.width / FLOAT_PANGO_SCALE;
-    logSize.height = log_rect.height / FLOAT_PANGO_SCALE;
+    aLogSize.width = log_rect.width / FLOAT_PANGO_SCALE;
+    aLogSize.height = log_rect.height / FLOAT_PANGO_SCALE;
 
     pango_glyph_string_free(glstr);
-    pango_item_free(item);
-    g_list_free(items);
 }
 
 // rounding and truncation functions for a Freetype floating point number 
@@ -463,22 +511,10 @@ gfxPangoFont::GetMetrics()
     if (mHasMetrics)
         return mMetrics;
 
-    RealizeFont();
-
-    PangoAttrList *al = pango_attr_list_new();
-    GList *items = pango_itemize(mPangoCtx, "a", 0, 1, al, NULL);
-    pango_attr_list_unref(al);
-
-    if (!items || g_list_length(items) != 1)
-        return mMetrics;        // XXX error
-
 #ifndef THEBES_USE_PANGO_CAIRO
     float val;
 
-    PangoItem *item = (PangoItem*)items->data;
-    PangoFcFont *fcfont = PANGO_FC_FONT(item->analysis.font);
-
-    XftFont *xftFont = pango_xft_font_get_font(PANGO_FONT(fcfont));
+    XftFont *xftFont = GetXftFont(); // RealizeFont is called here.
     if (!xftFont)
         return mMetrics;        // XXX error
 
@@ -487,6 +523,7 @@ gfxPangoFont::GetMetrics()
         return mMetrics;        // XXX error
 
     int size;
+    PangoFcFont *fcfont = PANGO_FC_FONT(mPangoFont);
     if (FcPatternGetInteger(fcfont->font_pattern, FC_PIXEL_SIZE, 0, &size) != FcResultMatch)
         size = 12;
     mMetrics.emHeight = PR_MAX(1, size);
@@ -508,12 +545,12 @@ gfxPangoFont::GetMetrics()
     mMetrics.maxAdvance = xftFont->max_advance_width;
 
     gfxSize isz, lsz;
-    GetSize(" ", 1, isz, lsz);
+    GetCharSize(' ', isz, lsz);
     mMetrics.spaceWidth = lsz.width;
 
     // XXX do some FcCharSetHasChar work here to make sure
     // we have an "x"
-    GetSize("x", 1, isz, lsz);
+    GetCharSize('x', isz, lsz);
     mMetrics.xHeight = isz.height;
     mMetrics.aveCharWidth = isz.width;
 
@@ -558,8 +595,7 @@ gfxPangoFont::GetMetrics()
     XftUnlockFace(xftFont);
 #else
     /* pango_cairo case; try to get all the metrics from pango itself */
-    PangoItem *item = (PangoItem*)items->data;
-    PangoFont *font = item->analysis.font;
+    PangoFont *font = GetPangoFont(); // RealizeFont is called here.
 
     PangoFontMetrics *pfm = pango_font_get_metrics (font, NULL);
 
@@ -585,9 +621,9 @@ gfxPangoFont::GetMetrics()
     mMetrics.maxAdvance = pango_font_metrics_get_approximate_char_width(pfm) / FLOAT_PANGO_SCALE; // XXX
 
     gfxSize isz, lsz;
-    GetSize(" ", 1, isz, lsz);
+    GetCharSize(' ', isz, lsz);
     mMetrics.spaceWidth = lsz.width;
-    GetSize("x", 1, isz, lsz);
+    GetCharSize('x', isz, lsz);
     mMetrics.xHeight = isz.height;
 
     mMetrics.aveCharWidth = pango_font_metrics_get_approximate_char_width(pfm) / FLOAT_PANGO_SCALE;
@@ -620,17 +656,34 @@ gfxPangoFont::GetMetrics()
     return mMetrics;
 }
 
-void
-gfxPangoFont::GetMozLang(nsACString &aMozLang)
+PRBool
+gfxPangoFont::HasGlyph(PRUint32 aChar)
 {
-    aMozLang.Assign(GetStyle()->langGroup);
-}
+    // Ensure that null character should be missing.
+    if (aChar == 0)
+        return PR_FALSE;
 
-PangoFont *
-gfxPangoFont::GetPangoFont()
-{
-    RealizeFont();
-    return pango_context_load_font(mPangoCtx, mPangoFontDesc);
+    PangoFont *font = nsnull;
+    if (mPangoFont)
+        font = mPangoFont;
+    else if (mGlyphTestingFont)
+        font = mGlyphTestingFont;
+    else {
+        gfxPangoFontNameMap *fontNameMap = gfxPangoFontNameMap::GetPangoFontNameMap();
+        NS_ENSURE_TRUE(fontNameMap, PR_FALSE);
+        // XXX in a prinsiple, we need to add weight and style for the key.
+        // But this method should be independent from pango for the performance.
+        // For the temporary, the name is enough for the key. The members of
+        // a font-family should have same glyphs.
+        NS_ConvertUTF16toUTF8 name(mName);
+        mGlyphTestingFont = fontNameMap->Get(name);
+        if (!mGlyphTestingFont) {
+            font = GetPangoFont();
+            NS_ENSURE_TRUE(font, PR_FALSE);
+        } else
+            font = mGlyphTestingFont;
+    }
+    return pango_fc_font_has_char(PANGO_FC_FONT(font), aChar) ? PR_TRUE : PR_FALSE;
 }
 
 nsString
@@ -721,7 +774,7 @@ gfxPangoFontGroup::MakeTextRun(const PRUint8 *aString, PRUint32 aLength,
         // We don't need to send an override character here, the characters must be all
         // LTR
         const gchar *utf8Chars = NS_REINTERPRET_CAST(const gchar*, aString);
-        InitTextRun(run, utf8Chars, aLength, 0, nsnull, 0);
+        InitTextRun(run, utf8Chars, aLength, 0);
     } else {
         const char *chars = NS_REINTERPRET_CAST(const char*, aString);
         // XXX this could be more efficient.
@@ -732,7 +785,7 @@ gfxPangoFontGroup::MakeTextRun(const PRUint8 *aString, PRUint32 aLength,
         nsCAutoString utf8;
         PRInt32 headerLen = AppendDirectionalIndicatorUTF8(isRTL, utf8);
         AppendUTF16toUTF8(unicodeString, utf8);
-        InitTextRun(run, utf8.get(), utf8.Length(), headerLen, nsnull, 0);
+        InitTextRun(run, utf8.get(), utf8.Length(), headerLen);
     }
     return run;
 }
@@ -750,14 +803,13 @@ gfxPangoFontGroup::MakeTextRun(const PRUnichar *aString, PRUint32 aLength,
     nsCAutoString utf8;
     PRInt32 headerLen = AppendDirectionalIndicatorUTF8(run->IsRightToLeft(), utf8);
     AppendUTF16toUTF8(Substring(aString, aString + aLength), utf8);
-    InitTextRun(run, utf8.get(), utf8.Length(), headerLen, aString, aLength);
+    InitTextRun(run, utf8.get(), utf8.Length(), headerLen);
     return run;
 }
 
 void
 gfxPangoFontGroup::InitTextRun(gfxTextRun *aTextRun, const gchar *aUTF8Text,
-                               PRUint32 aUTF8Length, PRUint32 aUTF8HeaderLength,
-                               const PRUnichar *aUTF16Text, PRUint32 aUTF16Length)
+                               PRUint32 aUTF8Length, PRUint32 aUTF8HeaderLength)
 {
 #if defined(ENABLE_XFT_FAST_PATH_ALWAYS)
     CreateGlyphRunsXft(aTextRun, aUTF8Text + aUTF8HeaderLength, aUTF8Length - aUTF8HeaderLength);
@@ -773,11 +825,7 @@ gfxPangoFontGroup::InitTextRun(gfxTextRun *aTextRun, const gchar *aUTF8Text,
                                (aTextRun->IsRightToLeft()
                                   ? PANGO_DIRECTION_RTL : PANGO_DIRECTION_LTR));
 
-    nsresult rv = CreateGlyphRunsFast(aTextRun, aUTF8Text + aUTF8HeaderLength,
-                                      aUTF8Length - aUTF8HeaderLength, aUTF16Text, aUTF16Length);
-    if (rv == NS_ERROR_FAILURE) {
-        CreateGlyphRunsItemizing(aTextRun, aUTF8Text, aUTF8Length, aUTF8HeaderLength);
-    }
+    CreateGlyphRunsItemizing(aTextRun, aUTF8Text, aUTF8Length, aUTF8HeaderLength);
 #endif
 }
 
@@ -1123,6 +1171,33 @@ gfxPangoFontGroup::SetGlyphs(gfxTextRun *aTextRun,
     return NS_OK;
 }
 
+nsresult
+gfxPangoFontGroup::SetMissingGlyphs(gfxTextRun *aTextRun,
+                                    const gchar *aUTF8, PRUint32 aUTF8Length,
+                                    PRUint32 *aUTF16Offset)
+{
+    PRUint32 utf16Offset = *aUTF16Offset;
+    PRUint32 textRunLength = aTextRun->GetLength();
+    for (PRUint32 index = 0; index < aUTF8Length;) {
+        if (utf16Offset >= textRunLength) {
+          NS_ERROR("Someone has added too many glyphs!");
+          break;
+        }
+        gunichar ch = g_utf8_get_char(aUTF8 + index);
+        SetMissingGlyphForUCS4(aTextRun, utf16Offset, ch);
+
+        ++utf16Offset;
+        NS_ASSERTION(!IS_SURROGATE(ch), "surrogates should not appear in UTF8");
+        if (ch >= 0x10000)
+            ++utf16Offset;
+        // We produced this UTF8 so we don't need to worry about malformed stuff
+        index = g_utf8_next_char(aUTF8 + index) - aUTF8;
+    }
+
+    *aUTF16Offset = utf16Offset;
+    return NS_OK;
+}
+
 #if defined(ENABLE_XFT_FAST_PATH_8BIT) || defined(ENABLE_XFT_FAST_PATH_ALWAYS)
 void
 gfxPangoFontGroup::CreateGlyphRunsXft(gfxTextRun *aTextRun,
@@ -1192,72 +1267,6 @@ gfxPangoFontGroup::CreateGlyphRunsXft(gfxTextRun *aTextRun,
 }
 #endif
 
-nsresult
-gfxPangoFontGroup::CreateGlyphRunsFast(gfxTextRun *aTextRun,
-                                       const gchar *aUTF8, PRUint32 aUTF8Length,
-                                       const PRUnichar *aUTF16, PRUint32 aUTF16Length)
-{
-    gfxPangoFont *font = GetFontAt(0);
-    PangoAnalysis analysis;
-    analysis.font        = font->GetPangoFont();
-    analysis.level       = aTextRun->IsRightToLeft() ? 1 : 0;
-    analysis.lang_engine = nsnull;
-    analysis.extra_attrs = nsnull;
-
-    // Find non-ASCII character for finding the language of the script.
-    guint32 ch = 'a';
-    PRUint8 unicharRange = kRangeSetLatin;
-    if (aUTF16) {
-        PRUint32 i;
-        for (i = 0; i < aUTF16Length; ++i) {
-            PRUnichar utf16Char = aUTF16[i];
-            if (utf16Char > 0x100) {
-                ch = utf16Char;
-                unicharRange = FindCharUnicodeRange(utf16Char);
-                break;
-            }
-        }
-    }
-
-    // Determin the language for finding the shaper.
-    nsCAutoString lang;
-    font->GetMozLang(lang);
-    switch (unicharRange) {
-        case kRangeSetLatin:
-            lang.Assign("x-western");
-            break;
-        case kRangeSetCJK:
-            if (GetCJKLangGroupIndex(lang.get()) < 0)
-                return NS_ERROR_FAILURE; // try with itemizing
-            break;
-        default:
-            lang.Assign(LangGroupFromUnicodeRange(unicharRange));
-            break;
-    }
-
-    if (lang.IsEmpty() || lang.Equals("x-unicode") || lang.Equals("x-user-def"))
-        return NS_ERROR_FAILURE; // try with itemizing
-
-    analysis.language     = GetPangoLanguage(lang);
-    analysis.shape_engine = pango_font_find_shaper(analysis.font,
-                                                   analysis.language,
-                                                   ch);
-
-    SetupClusterBoundaries(aTextRun, aUTF8, aUTF8Length, 0, &analysis);
-
-    PangoGlyphString *glyphString = pango_glyph_string_new();
-
-    pango_shape(aUTF8, aUTF8Length, &analysis, glyphString);
-
-    PRUint32 utf16Offset = 0;
-    nsresult rv = aTextRun->AddGlyphRun(font, 0);
-    if (NS_FAILED(rv))
-        return rv;
-    rv = SetGlyphs(aTextRun, aUTF8, aUTF8Length, &utf16Offset, glyphString, 0, PR_TRUE);
-    pango_glyph_string_free(glyphString);
-    return rv;
-}
-
 class FontSelector
 {
 public:
@@ -1266,7 +1275,7 @@ public:
                  PangoItem *aItem, PRUint32 aUTF16Offset, PRPackedBool aIsRTL) :
         mItem(aItem),
         mGroup(aGroup), mTextRun(aTextRun), mString(aString),
-        mFontIndex(0), mLength(aLength), mSegmentOffset(0), mUTF16Offset(aUTF16Offset),
+        mFontIndex(0), mLength(aLength), mUTF16Offset(aUTF16Offset),
         mTriedPrefFonts(0), mTriedOtherFonts(0), mIsRTL(aIsRTL)
     {
         for (PRUint32 i = 0; i < mGroup->FontListLength(); ++i)
@@ -1274,9 +1283,9 @@ public:
         mSpaceWidth = NS_lround(mGroup->GetFontAt(0)->GetMetrics().spaceWidth * FLOAT_PANGO_SCALE);
     }
     
-    void Run()
+    nsresult Run()
     {
-        InitSegments(0, mLength, mFontIndex);
+        return InitSegments(mString, mLength);
     }
 
     PRUint32 GetUTF16Offset() { return mUTF16Offset; }
@@ -1311,30 +1320,6 @@ public:
         return PR_TRUE;
     }
 
-    PRBool AppendNextSegment(gfxPangoFont *aFont, PRUint32 aUTF8Length,
-                             PangoGlyphString *aGlyphs, PRBool aGotGlyphs)
-    {
-        PangoFont *pf = aFont->GetPangoFont();
-        PRUint32 incomingUTF16Offset = mUTF16Offset;
-
-        if (!aGotGlyphs) {
-            // we can't use the existing glyphstring.
-            PangoFont *tmpFont = mItem->analysis.font;
-            mItem->analysis.font = pf;
-            pango_shape(mString + mSegmentOffset, aUTF8Length, &mItem->analysis, aGlyphs);
-            mItem->analysis.font = tmpFont;
-        }
-
-        nsresult rv = mTextRun->AddGlyphRun(aFont, incomingUTF16Offset);
-        if (NS_FAILED(rv))
-            return rv;
-        mGroup->SetGlyphs(mTextRun, mString + mSegmentOffset, aUTF8Length, &mUTF16Offset,
-                          aGlyphs, mSpaceWidth, PR_FALSE);
-
-        mSegmentOffset += aUTF8Length;
-        return NS_OK;
-    }
-
 private:
     PangoItem *mItem;
 
@@ -1345,7 +1330,6 @@ private:
     const char        *mString; // UTF-8
     PRUint32           mFontIndex;
     PRInt32            mLength;
-    PRUint32           mSegmentOffset;
     PRUint32           mUTF16Offset;
     PRUint32           mSpaceWidth;
 
@@ -1353,108 +1337,102 @@ private:
     PRPackedBool mTriedOtherFonts;
     PRPackedBool mIsRTL;
 
-    void InitSegments(const PRUint32 aOffset,
-                      const PRUint32 aLength,
-                      const PRUint32 aFontIndex) {
-        mFontIndex = aFontIndex;
-
-        const char *current = mString + aOffset;
-        PRBool checkMissingGlyph = PR_TRUE;
-
-        // for RTL, if we cannot find the font that has all glyphs,
-        // we should use better font.
-        PRUint32 betterFontIndex  = 0;
-        PRUint32 foundGlyphs      = 0;
-
-        PangoGlyphString *glyphString = pango_glyph_string_new();
+    nsresult InitSegments(const gchar *aUTF8, PRUint32 aLength) {
+        if (aLength == 0)
+            return NS_OK;
+        const gchar *start = aUTF8;
+        const gchar *last = start + aLength;
 
 RetryNextFont:
         nsRefPtr<gfxPangoFont> font = GetNextFont();
 
         // If we cannot found the font that has the current character glyph,
         // we should return default font's missing data.
-        if (!font) {
-            font = mFonts[betterFontIndex];
-            checkMissingGlyph = PR_FALSE;
+        if (!font)
+            return AppendMissingSegment(start, last - start);
+
+        nsresult rv;
+        for (const gchar *c = start; c < last;) {
+            // find the first missing glyph
+            gunichar u = g_utf8_get_char(c);
+            if (font->HasGlyph(PRUint32(u))) {
+                c = g_utf8_next_char(c);
+                continue;
+            }
+
+            // find the next point that can be renderd with current font
+            const gchar *missingStart = c;
+            const gchar *next;
+            for (next = g_utf8_next_char(missingStart); next < last; next = g_utf8_next_char(next)) {
+                u = g_utf8_get_char(next);
+                if (font->HasGlyph(PRUint32(u)))
+                    break;
+            }
+
+            // current font has 0 glyphs for current segment, try with next font
+            if (missingStart == start && next == last)
+                goto RetryNextFont;
+
+            // create the segment for found glyphs
+            rv = AppendSegment(font, start, missingStart - start);
+            NS_ENSURE_SUCCESS(rv, rv);
+
+            // init the missing glyphs with remains fonts.
+            PRUint32 fontIndex = mFontIndex;
+            rv = InitSegments(missingStart, next - missingStart);
+            mFontIndex = fontIndex;
+            NS_ENSURE_SUCCESS(rv, rv);
+
+            start = c = next;
         }
 
-        // Shaping
+        rv = AppendSegment(font, start, last - start);
+        NS_ENSURE_SUCCESS(rv, rv);
+        return NS_OK;
+    }
+
+    nsresult AppendSegment(gfxPangoFont* aFont, const gchar *aUTF8, PRUint32 aLength) {
+        if (aLength == 0)
+            return NS_OK;
+
+        PangoFont* pf = aFont->GetPangoFont();
+
+        PangoGlyphString *glyphString = pango_glyph_string_new();
+        if (!glyphString)
+            return NS_ERROR_OUT_OF_MEMORY;
         PangoFont *tmpFont = mItem->analysis.font;
-        mItem->analysis.font = font->GetPangoFont();
-        pango_shape(current, aLength, &mItem->analysis, glyphString);
+        mItem->analysis.font = pf;
+        pango_shape(aUTF8, aLength, &mItem->analysis, glyphString);
         mItem->analysis.font = tmpFont;
 
-        gint num_glyphs     = glyphString->num_glyphs;
-        gint *clusters      = glyphString->log_clusters;
-        PRUint32 offset     = aOffset;
-        PRUint32 skipLength = 0;
-        if (checkMissingGlyph) {
-            for (PRInt32 i = 0; i < num_glyphs; ++i) {
-                PangoGlyphInfo *info = &glyphString->glyphs[i];
-                if (IS_MISSING_GLYPH(info->glyph)) {
-                    // XXX Note that we don't support the segment separation
-                    // in RTL text. Because the Arabic characters changes the
-                    // glyphs by the position of the context. I think that the
-                    // languages of RTL doesn't have *very *many characters, so,
-                    // the Arabic/Hebrew font may have all glyphs in a font.
-                    if (mIsRTL) {
-                        PRUint32 found = i;
-                        for (PRInt32 j = i; j < num_glyphs; ++j) {
-                            info = &glyphString->glyphs[j];
-                            if (!IS_MISSING_GLYPH(info->glyph))
-                                found++;
-                        }
-                        if (found > foundGlyphs) {
-                            // we find better font!
-                            foundGlyphs = found;
-                            betterFontIndex = mFontIndex - 1;
-                        }
-                        goto RetryNextFont;
-                    }
-
-                    // The glyph is missing, separate segment here.
-                    PRUint32 missingLength = aLength - clusters[i];
-                    PRInt32 j;
-                    for (j = i + 1; j < num_glyphs; ++j) {
-                        info = &glyphString->glyphs[j];
-                        if (!IS_MISSING_GLYPH(info->glyph)) {
-                            missingLength = aOffset + clusters[j] - offset;
-                            break;
-                        }
-                    }
-
-                    if (i != 0) {
-                        // found glyphs
-                        AppendNextSegment(font, offset - (aOffset + skipLength),
-                                          glyphString, PR_FALSE);
-                    }
-
-                    // missing glyphs
-                    PRUint32 fontIndex = mFontIndex;
-                    InitSegments(offset, missingLength, mFontIndex);
-                    mFontIndex = fontIndex;
-
-                    PRUint32 next = offset + missingLength;
-                    if (next >= aLength) {
-                        pango_glyph_string_free(glyphString);
-                        return;
-                    }
-
-                    // remains, continue this loop
-                    i = j;
-                    skipLength = next - aOffset;
-                }
-                if (i + 1 < num_glyphs)
-                    offset = aOffset + clusters[i + 1];
-                else
-                    offset = aOffset + aLength;
-            }
-        } else {
-            offset = aOffset + aLength;
+        nsresult rv = mTextRun->AddGlyphRun(aFont, mUTF16Offset);
+        if (NS_FAILED(rv)) {
+            NS_ERROR("AddGlyphRun Failed");
+            pango_glyph_string_free(glyphString);
+            return rv;
         }
-
-        AppendNextSegment(font, aLength - skipLength, glyphString, skipLength == 0);
+        PRUint32 utf16Offset = mUTF16Offset;
+        rv = mGroup->SetGlyphs(mTextRun, aUTF8, aLength,
+                               &utf16Offset, glyphString, mSpaceWidth, PR_FALSE);
         pango_glyph_string_free(glyphString);
+        NS_ENSURE_SUCCESS(rv, rv);
+
+        mUTF16Offset = utf16Offset;
+        return NS_OK;
+    }
+
+    nsresult AppendMissingSegment(const gchar *aUTF8, PRUint32 aLength) {
+        if (aLength == 0)
+            return NS_OK;
+
+        nsresult rv = mTextRun->AddGlyphRun(mFonts[0], mUTF16Offset);
+        NS_ENSURE_SUCCESS(rv, rv);
+        PRUint32 utf16Offset = mUTF16Offset;
+        rv = mGroup->SetMissingGlyphs(mTextRun, aUTF8, aLength, &utf16Offset);
+        NS_ENSURE_SUCCESS(rv, rv);
+
+        mUTF16Offset = utf16Offset;
+        return NS_OK;
     }
 
     gfxPangoFont *GetNextFont() {
@@ -1524,7 +1502,7 @@ TRY_AGAIN_HOPE_FOR_THE_BEST_2:
        if (!prefBranch)
            return;
 
-       // Add by the order of accept languages.
+       // Add the accept languages.
        nsXPIDLCString list;
        nsresult rv = prefBranch->GetCharPref("intl.accept_languages",
                                              getter_Copies(list));
@@ -1883,3 +1861,72 @@ GetMozLanguage(const PangoLanguage *aLang, nsACString &aMozLang)
         break;
     }
 }
+
+gfxPangoFontCache::gfxPangoFontCache()
+{
+    mPangoFonts.Init(500);
+}
+
+gfxPangoFontCache::~gfxPangoFontCache()
+{
+}
+
+void
+gfxPangoFontCache::Put(const PangoFontDescription *aFontDesc, PangoFont *aPangoFont)
+{
+    if (mPangoFonts.Count() > 5000)
+        mPangoFonts.Clear();
+    PRUint32 key = pango_font_description_hash(aFontDesc);
+    gfxPangoFontWrapper *value = new gfxPangoFontWrapper(aPangoFont);
+    if (!value)
+        return;
+    mPangoFonts.Put(key, value);
+}
+
+PangoFont*
+gfxPangoFontCache::Get(const PangoFontDescription *aFontDesc)
+{
+    PRUint32 key = pango_font_description_hash(aFontDesc);
+    gfxPangoFontWrapper *value;
+    if (!mPangoFonts.Get(key, &value))
+        return nsnull;
+    PangoFont *font = value->Get();
+    g_object_ref(font);
+    return font;
+}
+
+gfxPangoFontNameMap::gfxPangoFontNameMap()
+{
+    mPangoFonts.Init(100);
+}
+
+gfxPangoFontNameMap::~gfxPangoFontNameMap()
+{
+}
+
+void
+gfxPangoFontNameMap::Put(const nsACString &aName, PangoFont *aPangoFont)
+{
+    nsCAutoString key(aName);
+    ToLowerCase(key);
+    gfxPangoFontWrapper *value;
+    if (!mPangoFonts.Get(key, &value)) {
+        value = new gfxPangoFontWrapper(aPangoFont);
+        if (!value)
+            return;
+        mPangoFonts.Put(key, value);
+    }
+}
+
+PangoFont*
+gfxPangoFontNameMap::Get(const nsACString &aName)
+{
+    nsCAutoString key(aName);
+    ToLowerCase(key);
+    gfxPangoFontWrapper *value;
+    if (!mPangoFonts.Get(key, &value))
+        return nsnull;
+    PangoFont *font = value->Get();
+    g_object_ref(font);
+    return font;
+}