Revert of Fix color emoji. (patchset #11 id:320001 of https://codereview.chromium.org/636183005/)

Reason for revert:
Crashing the Windows bots.

Original issue's description:
> Fix color emoji.
>
> Removes the GrMaskFormat and single atlas in GrTextStrike.
> Replaces it by storing the GrMaskFormat in each GrGlyph, and
> doing a lookup for the correct atlas based on that.
>
> Disables color glyph rendering in GrDistanceFieldTextContext
> for now.
>
> BUG=skia:2887
>
> Committed: https://skia.googlesource.com/skia/+/bc92163ddfe957ad6ffbb02ac40e0ba75ff82216

TBR=robertphillips@google.com,bungeman@google.com,reed@google.com,bsalomon@google.com
NOTREECHECKS=true
NOTRY=true
BUG=skia:2887

Review URL: https://codereview.chromium.org/640413004
diff --git a/src/gpu/GrDistanceFieldTextContext.cpp b/src/gpu/GrDistanceFieldTextContext.cpp
index a1f5ce6..baba10d 100755
--- a/src/gpu/GrDistanceFieldTextContext.cpp
+++ b/src/gpu/GrDistanceFieldTextContext.cpp
@@ -412,11 +412,6 @@
         return;
     }
 
-    // TODO: support color glyphs
-    if (kA8_GrMaskFormat != glyph->fMaskFormat) {
-        return;
-    }
-
     SkScalar sx = SkFixedToScalar(vx);
     SkScalar sy = SkFixedToScalar(vy);
 /*
@@ -445,7 +440,7 @@
             }
 
             // try to clear out an unused plot before we flush
-            if (fContext->getFontCache()->freeUnusedPlot(fStrike, glyph) &&
+            if (fContext->getFontCache()->freeUnusedPlot(fStrike) &&
                 fStrike->addGlyphToAtlas(glyph, scaler)) {
                 goto HAS_ATLAS;
             }
@@ -461,7 +456,7 @@
             fContext->flush();
 
             // we should have an unused plot now
-            if (fContext->getFontCache()->freeUnusedPlot(fStrike, glyph) &&
+            if (fContext->getFontCache()->freeUnusedPlot(fStrike) &&
                 fStrike->addGlyphToAtlas(glyph, scaler)) {
                 goto HAS_ATLAS;
             }