Only use fake gamma with linear devices.

src/gpu/text/GrStencilAndCoverTextContext.cpp

Index: src/gpu/text/GrStencilAndCoverTextContext.cpp
diff --git a/src/gpu/text/GrStencilAndCoverTextContext.cpp b/src/gpu/text/GrStencilAndCoverTextContext.cpp
index 205c6d976a9e079defe601208d96f3c71de694e4..a87e5d2b9d71a613c8a1ef92989bf9e0bb9f54a2 100644
--- a/src/gpu/text/GrStencilAndCoverTextContext.cpp
+++ b/src/gpu/text/GrStencilAndCoverTextContext.cpp
@@ -629,7 +629,7 @@ void GrStencilAndCoverTextContext::TextRun::draw(GrContext* ctx,
 
 SkGlyphCache* GrStencilAndCoverTextContext::TextRun::getGlyphCache() const {
     if (!fDetachedGlyphCache) {
-        fDetachedGlyphCache = fFont.detachCache(nullptr, nullptr, true /*ignoreGamma*/);
+        fDetachedGlyphCache = fFont.detachCache(nullptr, SkPaint::FakeGamma::Off, nullptr);
     }
     return fDetachedGlyphCache;
 }