Decouple contrast boost from fake gamma.

src/core/SkDraw.cpp

Index: src/core/SkDraw.cpp
diff --git a/src/core/SkDraw.cpp b/src/core/SkDraw.cpp
index c63c90fb8ac8825e0e36949aeb2af1af72968490..232973488e82d388143f5fa3f1d2760fc7d23d13 100644
--- a/src/core/SkDraw.cpp
+++ b/src/core/SkDraw.cpp
@@ -1555,8 +1555,12 @@ private:
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-SkPaint::FakeGamma SkDraw::fakeGamma() const {
-    return fDevice->imageInfo().isLinear() ? SkPaint::FakeGamma::On : SkPaint::FakeGamma::Off;
+uint32_t SkDraw::scalerContextFlags() const {
+    uint32_t flags = SkPaint::kBoostContrast_ScalerContextFlag;
+    if (fDevice->imageInfo().isLinear()) {
+        flags |= SkPaint::kFakeGamma_ScalerContextFlag;
+    }
+    return flags;
 }
 
 void SkDraw::drawText(const char text[], size_t byteLength,
@@ -1577,7 +1581,7 @@ void SkDraw::drawText(const char text[], size_t byteLength,
         return;
     }
 
-    SkAutoGlyphCache cache(paint, &fDevice->surfaceProps(), this->fakeGamma(), fMatrix);
+    SkAutoGlyphCache cache(paint, &fDevice->surfaceProps(), this->scalerContextFlags(), fMatrix);
 
     // The Blitter Choose needs to be live while using the blitter below.
     SkAutoBlitterChoose    blitterChooser(fDst, *fMatrix, paint);
@@ -1606,7 +1610,7 @@ void SkDraw::drawPosText_asPaths(const char text[], size_t byteLength,
     paint.setPathEffect(nullptr);
 
     SkPaint::GlyphCacheProc glyphCacheProc = paint.getGlyphCacheProc(true);
-    SkAutoGlyphCache        cache(paint, &fDevice->surfaceProps(), this->fakeGamma(), nullptr);
+    SkAutoGlyphCache cache(paint, &fDevice->surfaceProps(), this->scalerContextFlags(), nullptr);
 
     const char*        stop = text + byteLength;
     SkTextAlignProc    alignProc(paint.getTextAlign());
@@ -1657,7 +1661,7 @@ void SkDraw::drawPosText(const char text[], size_t byteLength,
         return;
     }
 
-    SkAutoGlyphCache cache(paint, &fDevice->surfaceProps(), this->fakeGamma(), fMatrix);
+    SkAutoGlyphCache cache(paint, &fDevice->surfaceProps(), this->scalerContextFlags(), fMatrix);
 
     // The Blitter Choose needs to be live while using the blitter below.
     SkAutoBlitterChoose    blitterChooser(fDst, *fMatrix, paint);