--- a/gfx/thebes/gfxDWriteFonts.cpp
+++ b/gfx/thebes/gfxDWriteFonts.cpp
@@ -311,32 +311,29 @@ gfxDWriteFont::ComputeMetrics(AntialiasO
     mMetrics->underlineOffset =
         fontMetrics.underlinePosition * mFUnitsConvFactor;
     mMetrics->underlineSize = 
         fontMetrics.underlineThickness * mFUnitsConvFactor;
     mMetrics->strikeoutOffset =
         fontMetrics.strikethroughPosition * mFUnitsConvFactor;
     mMetrics->strikeoutSize =
         fontMetrics.strikethroughThickness * mFUnitsConvFactor;
-    mMetrics->superscriptOffset = 0;
-    mMetrics->subscriptOffset = 0;
 
     SanitizeMetrics(mMetrics, GetFontEntry()->mIsBadUnderlineFont);
 
 #if 0
     printf("Font: %p (%s) size: %f\n", this,
            NS_ConvertUTF16toUTF8(GetName()).get(), mStyle.size);
     printf("    emHeight: %f emAscent: %f emDescent: %f\n", mMetrics->emHeight, mMetrics->emAscent, mMetrics->emDescent);
     printf("    maxAscent: %f maxDescent: %f maxAdvance: %f\n", mMetrics->maxAscent, mMetrics->maxDescent, mMetrics->maxAdvance);
     printf("    internalLeading: %f externalLeading: %f\n", mMetrics->internalLeading, mMetrics->externalLeading);
     printf("    spaceWidth: %f aveCharWidth: %f zeroOrAve: %f xHeight: %f\n",
            mMetrics->spaceWidth, mMetrics->aveCharWidth, mMetrics->zeroOrAveCharWidth, mMetrics->xHeight);
-    printf("    uOff: %f uSize: %f stOff: %f stSize: %f supOff: %f subOff: %f\n",
-           mMetrics->underlineOffset, mMetrics->underlineSize, mMetrics->strikeoutOffset, mMetrics->strikeoutSize,
-           mMetrics->superscriptOffset, mMetrics->subscriptOffset);
+    printf("    uOff: %f uSize: %f stOff: %f stSize: %f\n",
+           mMetrics->underlineOffset, mMetrics->underlineSize, mMetrics->strikeoutOffset, mMetrics->strikeoutSize);
 #endif
 }
 
 using namespace mozilla; // for AutoSwap_* types
 
 struct EBLCHeader {
     AutoSwap_PRUint32 version;
     AutoSwap_PRUint32 numSizes;

--- a/gfx/thebes/gfxFT2FontBase.cpp
+++ b/gfx/thebes/gfxFT2FontBase.cpp
@@ -128,17 +128,17 @@ gfxFT2FontBase::GetMetrics()
     //    printf("font name: %s %f\n", NS_ConvertUTF16toUTF8(GetName()).get(), GetStyle()->size);
     //    printf ("pango font %s\n", pango_font_description_to_string (pango_font_describe (font)));
 
     fprintf (stderr, "Font: %s\n", NS_ConvertUTF16toUTF8(GetName()).get());
     fprintf (stderr, "    emHeight: %f emAscent: %f emDescent: %f\n", mMetrics.emHeight, mMetrics.emAscent, mMetrics.emDescent);
     fprintf (stderr, "    maxAscent: %f maxDescent: %f\n", mMetrics.maxAscent, mMetrics.maxDescent);
     fprintf (stderr, "    internalLeading: %f externalLeading: %f\n", mMetrics.externalLeading, mMetrics.internalLeading);
     fprintf (stderr, "    spaceWidth: %f aveCharWidth: %f xHeight: %f\n", mMetrics.spaceWidth, mMetrics.aveCharWidth, mMetrics.xHeight);
-    fprintf (stderr, "    uOff: %f uSize: %f stOff: %f stSize: %f suOff: %f suSize: %f\n", mMetrics.underlineOffset, mMetrics.underlineSize, mMetrics.strikeoutOffset, mMetrics.strikeoutSize, mMetrics.superscriptOffset, mMetrics.subscriptOffset);
+    fprintf (stderr, "    uOff: %f uSize: %f stOff: %f stSize: %f\n", mMetrics.underlineOffset, mMetrics.underlineSize, mMetrics.strikeoutOffset, mMetrics.strikeoutSize);
 #endif
 
     mHasMetrics = true;
     return mMetrics;
 }
 
 // Get the glyphID of a space
 uint32_t

--- a/gfx/thebes/gfxFT2Utils.cpp
+++ b/gfx/thebes/gfxFT2Utils.cpp
@@ -62,18 +62,16 @@ gfxFT2LockedFace::GetMetrics(gfxFont::Me
         aMetrics->externalLeading = 0.2 * emHeight;
         const gfxFloat spaceWidth = 0.5 * emHeight;
         aMetrics->spaceWidth = spaceWidth;
         aMetrics->maxAdvance = spaceWidth;
         aMetrics->aveCharWidth = spaceWidth;
         aMetrics->zeroOrAveCharWidth = spaceWidth;
         const gfxFloat xHeight = 0.5 * emHeight;
         aMetrics->xHeight = xHeight;
-        aMetrics->superscriptOffset = xHeight;
-        aMetrics->subscriptOffset = xHeight;
         const gfxFloat underlineSize = emHeight / 14.0;
         aMetrics->underlineSize = underlineSize;
         aMetrics->underlineOffset = -underlineSize;
         aMetrics->strikeoutOffset = 0.25 * emHeight;
         aMetrics->strikeoutSize = underlineSize;
 
         *aSpaceGlyph = 0;
         return;
@@ -238,34 +236,16 @@ gfxFT2LockedFace::GetMetrics(gfxFont::Me
     } else { // No strikeout info.
         aMetrics->strikeoutSize = aMetrics->underlineSize;
         // Use OpenType spec's suggested position for Roman font.
         aMetrics->strikeoutOffset = emHeight * 409.0 / 2048.0
             + 0.5 * aMetrics->strikeoutSize;
     }
     SnapLineToPixels(aMetrics->strikeoutOffset, aMetrics->strikeoutSize);
 
-    if (os2 && os2->ySuperscriptYOffset) {
-        gfxFloat val = ScaleRoundDesignUnits(os2->ySuperscriptYOffset,
-                                             ftMetrics.y_scale);
-        aMetrics->superscriptOffset = std::max(1.0, val);
-    } else {
-        aMetrics->superscriptOffset = aMetrics->xHeight;
-    }
-    
-    if (os2 && os2->ySubscriptYOffset) {
-        gfxFloat val = ScaleRoundDesignUnits(os2->ySubscriptYOffset,
-                                             ftMetrics.y_scale);
-        // some fonts have the incorrect sign. 
-        val = fabs(val);
-        aMetrics->subscriptOffset = std::max(1.0, val);
-    } else {
-        aMetrics->subscriptOffset = aMetrics->xHeight;
-    }
-
     aMetrics->maxHeight = aMetrics->maxAscent + aMetrics->maxDescent;
 
     // Make the line height an integer number of pixels so that lines will be
     // equally spaced (rather than just being snapped to pixels, some up and
     // some down).  Layout calculates line height from the emHeight +
     // internalLeading + externalLeading, but first each of these is rounded
     // to layout units.  To ensure that the result is an integer number of
     // pixels, round each of the components to pixels.

--- a/gfx/thebes/gfxFont.cpp
+++ b/gfx/thebes/gfxFont.cpp
@@ -4592,18 +4592,16 @@ gfxFont::InitMetricsFromSfntTables(Metri
             // version 2 and later includes the x-height field
             SET_SIGNED(xHeight, os2->sxHeight);
             // Abs because of negative xHeight seen in Kokonor (Tibetan) font
             aMetrics.xHeight = Abs(aMetrics.xHeight);
         }
         // this should always be present in any valid OS/2 of any version
         if (len >= offsetof(OS2Table, sTypoLineGap) + sizeof(int16_t)) {
             SET_SIGNED(aveCharWidth, os2->xAvgCharWidth);
-            SET_SIGNED(subscriptOffset, os2->ySubscriptYOffset);
-            SET_SIGNED(superscriptOffset, os2->ySuperscriptYOffset);
             SET_SIGNED(strikeoutSize, os2->yStrikeoutSize);
             SET_SIGNED(strikeoutOffset, os2->yStrikeoutPosition);
 
             // for fonts with USE_TYPO_METRICS set in the fsSelection field,
             // and for all OpenType math fonts (having a 'MATH' table),
             // let the OS/2 sTypo* metrics override those from the hhea table
             // (see http://www.microsoft.com/typography/otspec/os2.htm#fss)
             const uint16_t kUseTypoMetricsMask = 1 << 7;
@@ -4655,23 +4653,16 @@ void gfxFont::CalculateDerivedMetrics(Me
 
     if (GetFontEntry()->IsFixedPitch()) {
         // Some Quartz fonts are fixed pitch, but there's some glyph with a bigger
         // advance than the average character width... this forces
         // those fonts to be recognized like fixed pitch fonts by layout.
         aMetrics.maxAdvance = aMetrics.aveCharWidth;
     }
 
-    if (!aMetrics.subscriptOffset) {
-        aMetrics.subscriptOffset = aMetrics.xHeight;
-    }
-    if (!aMetrics.superscriptOffset) {
-        aMetrics.superscriptOffset = aMetrics.xHeight;
-    }
-
     if (!aMetrics.strikeoutOffset) {
         aMetrics.strikeoutOffset = aMetrics.xHeight * 0.5;
     }
     if (!aMetrics.strikeoutSize) {
         aMetrics.strikeoutSize = aMetrics.underlineSize;
     }
 }
 
@@ -4680,29 +4671,16 @@ gfxFont::SanitizeMetrics(gfxFont::Metric
 {
     // Even if this font size is zero, this font is created with non-zero size.
     // However, for layout and others, we should return the metrics of zero size font.
     if (mStyle.size == 0.0) {
         memset(aMetrics, 0, sizeof(gfxFont::Metrics));
         return;
     }
 
-    // MS (P)Gothic and MS (P)Mincho are not having suitable values in their super script offset.
-    // If the values are not suitable, we should use x-height instead of them.
-    // See https://bugzilla.mozilla.org/show_bug.cgi?id=353632
-    if (aMetrics->superscriptOffset <= 0 ||
-        aMetrics->superscriptOffset >= aMetrics->maxAscent) {
-        aMetrics->superscriptOffset = aMetrics->xHeight;
-    }
-    // And also checking the case of sub script offset. The old gfx for win has checked this too.
-    if (aMetrics->subscriptOffset <= 0 ||
-        aMetrics->subscriptOffset >= aMetrics->maxAscent) {
-        aMetrics->subscriptOffset = aMetrics->xHeight;
-    }
-
     aMetrics->underlineSize = std::max(1.0, aMetrics->underlineSize);
     aMetrics->strikeoutSize = std::max(1.0, aMetrics->strikeoutSize);
 
     aMetrics->underlineOffset = std::min(aMetrics->underlineOffset, -1.0);
 
     if (aMetrics->maxAscent < 1.0) {
         // We cannot draw strikeout line and overline in the ascent...
         aMetrics->underlineSize = 0;

--- a/gfx/thebes/gfxFont.h
+++ b/gfx/thebes/gfxFont.h
@@ -1653,18 +1653,16 @@ public:
     virtual mozilla::TemporaryRef<mozilla::gfx::GlyphRenderingOptions>
       GetGlyphRenderingOptions() { return nullptr; }
 
     gfxFloat SynthesizeSpaceWidth(uint32_t aCh);
 
     // Font metrics
     struct Metrics {
         gfxFloat xHeight;
-        gfxFloat superscriptOffset;
-        gfxFloat subscriptOffset;
         gfxFloat strikeoutSize;
         gfxFloat strikeoutOffset;
         gfxFloat underlineSize;
         gfxFloat underlineOffset;
 
         gfxFloat internalLeading;
         gfxFloat externalLeading;
 

--- a/gfx/thebes/gfxGDIFont.cpp
+++ b/gfx/thebes/gfxGDIFont.cpp
@@ -242,19 +242,16 @@ gfxGDIFont::Initialize()
 
     // Get font metrics if size > 0
     if (mAdjustedSize > 0.0) {
 
         OUTLINETEXTMETRIC oMetrics;
         TEXTMETRIC& metrics = oMetrics.otmTextMetrics;
 
         if (0 < GetOutlineTextMetrics(dc.GetDC(), sizeof(oMetrics), &oMetrics)) {
-            mMetrics->superscriptOffset = (double)oMetrics.otmptSuperscriptOffset.y;
-            // Some fonts have wrong sign on their subscript offset, bug 410917.
-            mMetrics->subscriptOffset = fabs((double)oMetrics.otmptSubscriptOffset.y);
             mMetrics->strikeoutSize = (double)oMetrics.otmsStrikeoutSize;
             mMetrics->strikeoutOffset = (double)oMetrics.otmsStrikeoutPosition;
             mMetrics->underlineSize = (double)oMetrics.otmsUnderscoreSize;
             mMetrics->underlineOffset = (double)oMetrics.otmsUnderscorePosition;
 
             const MAT2 kIdentityMatrix = { {0, 1}, {0, 0}, {0, 0}, {0, 1} };
             GLYPHMETRICS gm;
             DWORD len = GetGlyphOutlineW(dc.GetDC(), char16_t('x'), GGO_METRICS, &gm, 0, nullptr, &kIdentityMatrix);
@@ -283,18 +280,16 @@ gfxGDIFont::Initialize()
                 NS_WARNING("Missing or corrupt font data, fasten your seatbelt");
                 mIsValid = false;
                 memset(mMetrics, 0, sizeof(*mMetrics));
                 return;
             }
 
             mMetrics->xHeight =
                 ROUND((float)metrics.tmAscent * DEFAULT_XHEIGHT_FACTOR);
-            mMetrics->superscriptOffset = mMetrics->xHeight;
-            mMetrics->subscriptOffset = mMetrics->xHeight;
             mMetrics->strikeoutSize = 1;
             mMetrics->strikeoutOffset = ROUND(mMetrics->xHeight * 0.5f); // 50% of xHeight
             mMetrics->underlineSize = 1;
             mMetrics->underlineOffset = -ROUND((float)metrics.tmDescent * 0.30f); // 30% of descent
             mMetrics->emHeight = metrics.tmHeight - metrics.tmInternalLeading;
             mMetrics->emAscent = metrics.tmAscent - metrics.tmInternalLeading;
             mMetrics->emDescent = metrics.tmDescent;
         }
@@ -389,19 +384,18 @@ gfxGDIFont::Initialize()
 
 #if 0
     printf("Font: %p (%s) size: %f adjusted size: %f valid: %s\n", this,
            NS_ConvertUTF16toUTF8(GetName()).get(), mStyle.size, mAdjustedSize, (mIsValid ? "yes" : "no"));
     printf("    emHeight: %f emAscent: %f emDescent: %f\n", mMetrics->emHeight, mMetrics->emAscent, mMetrics->emDescent);
     printf("    maxAscent: %f maxDescent: %f maxAdvance: %f\n", mMetrics->maxAscent, mMetrics->maxDescent, mMetrics->maxAdvance);
     printf("    internalLeading: %f externalLeading: %f\n", mMetrics->internalLeading, mMetrics->externalLeading);
     printf("    spaceWidth: %f aveCharWidth: %f xHeight: %f\n", mMetrics->spaceWidth, mMetrics->aveCharWidth, mMetrics->xHeight);
-    printf("    uOff: %f uSize: %f stOff: %f stSize: %f supOff: %f subOff: %f\n",
-           mMetrics->underlineOffset, mMetrics->underlineSize, mMetrics->strikeoutOffset, mMetrics->strikeoutSize,
-           mMetrics->superscriptOffset, mMetrics->subscriptOffset);
+    printf("    uOff: %f uSize: %f stOff: %f stSize: %f\n",
+           mMetrics->underlineOffset, mMetrics->underlineSize, mMetrics->strikeoutOffset, mMetrics->strikeoutSize);
 #endif
 }
 
 void
 gfxGDIFont::FillLogFont(LOGFONTW& aLogFont, gfxFloat aSize,
                         bool aUseGDIFakeItalic)
 {
     GDIFontEntry *fe = static_cast<GDIFontEntry*>(GetFontEntry());

--- a/gfx/thebes/gfxMacFont.cpp
+++ b/gfx/thebes/gfxMacFont.cpp
@@ -327,17 +327,17 @@ gfxMacFont::InitMetrics()
 #if 0
     fprintf (stderr, "Font: %p (%s) size: %f\n", this,
              NS_ConvertUTF16toUTF8(GetName()).get(), mStyle.size);
 //    fprintf (stderr, "    fbounds.origin.x %f y %f size.width %f height %f\n", fbounds.origin.x, fbounds.origin.y, fbounds.size.width, fbounds.size.height);
     fprintf (stderr, "    emHeight: %f emAscent: %f emDescent: %f\n", mMetrics.emHeight, mMetrics.emAscent, mMetrics.emDescent);
     fprintf (stderr, "    maxAscent: %f maxDescent: %f maxAdvance: %f\n", mMetrics.maxAscent, mMetrics.maxDescent, mMetrics.maxAdvance);
     fprintf (stderr, "    internalLeading: %f externalLeading: %f\n", mMetrics.internalLeading, mMetrics.externalLeading);
     fprintf (stderr, "    spaceWidth: %f aveCharWidth: %f xHeight: %f\n", mMetrics.spaceWidth, mMetrics.aveCharWidth, mMetrics.xHeight);
-    fprintf (stderr, "    uOff: %f uSize: %f stOff: %f stSize: %f supOff: %f subOff: %f\n", mMetrics.underlineOffset, mMetrics.underlineSize, mMetrics.strikeoutOffset, mMetrics.strikeoutSize, mMetrics.superscriptOffset, mMetrics.subscriptOffset);
+    fprintf (stderr, "    uOff: %f uSize: %f stOff: %f stSize: %f\n", mMetrics.underlineOffset, mMetrics.underlineSize, mMetrics.strikeoutOffset, mMetrics.strikeoutSize);
 #endif
 }
 
 gfxFloat
 gfxMacFont::GetCharWidth(CFDataRef aCmap, char16_t aUniChar,
                          uint32_t *aGlyphID, gfxFloat aConvFactor)
 {
     CGGlyph glyph = 0;