Only use fake gamma with linear devices.

src/core/SkDraw.cpp

Index: src/core/SkDraw.cpp
diff --git a/src/core/SkDraw.cpp b/src/core/SkDraw.cpp
index d07bcb8fcf1e05364ea900a573081a32aabe1227..efacfda19c5e25435c7ca73f27589639a1867d29 100644
--- a/src/core/SkDraw.cpp
+++ b/src/core/SkDraw.cpp
@@ -1556,6 +1556,10 @@ private:
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+SkPaint::FakeGamma SkDraw::fakeGamma() const {
+    return fDevice->imageInfo().isLinear() ? SkPaint::FakeGamma::On : SkPaint::FakeGamma::Off;
+}
+
 void SkDraw::drawText(const char text[], size_t byteLength,
                       SkScalar x, SkScalar y, const SkPaint& paint) const {
     SkASSERT(byteLength == 0 || text != nullptr);
@@ -1574,17 +1578,16 @@ void SkDraw::drawText(const char text[], size_t byteLength,
         return;
     }
 
-    SkAutoGlyphCache       autoCache(paint, &fDevice->surfaceProps(), fMatrix);
-    SkGlyphCache*          cache = autoCache.getCache();
+    SkAutoGlyphCache cache(paint, &fDevice->surfaceProps(), this->fakeGamma(), fMatrix);
 
     // The Blitter Choose needs to be live while using the blitter below.
     SkAutoBlitterChoose    blitterChooser(fDst, *fMatrix, paint);
     SkAAClipBlitterWrapper wrapper(*fRC, blitterChooser.get());
-    DrawOneGlyph           drawOneGlyph(*this, paint, cache, wrapper.getBlitter());
+    DrawOneGlyph           drawOneGlyph(*this, paint, cache.get(), wrapper.getBlitter());
 
     SkFindAndPlaceGlyph::ProcessText(
         paint.getTextEncoding(), text, byteLength,
-        {x, y}, *fMatrix, paint.getTextAlign(), cache, drawOneGlyph);
+        {x, y}, *fMatrix, paint.getTextAlign(), cache.get(), drawOneGlyph);
 }
 
 //////////////////////////////////////////////////////////////////////////////
@@ -1604,8 +1607,7 @@ void SkDraw::drawPosText_asPaths(const char text[], size_t byteLength,
     paint.setPathEffect(nullptr);
 
     SkDrawCacheProc     glyphCacheProc = paint.getDrawCacheProc();
-    SkAutoGlyphCache    autoCache(paint, &fDevice->surfaceProps(), nullptr);
-    SkGlyphCache*       cache = autoCache.getCache();
+    SkAutoGlyphCache    cache(paint, &fDevice->surfaceProps(), this->fakeGamma(), nullptr);
 
     const char*        stop = text + byteLength;
     SkTextAlignProc    alignProc(paint.getTextAlign());
@@ -1616,7 +1618,7 @@ void SkDraw::drawPosText_asPaths(const char text[], size_t byteLength,
     paint.setPathEffect(origPaint.getPathEffect());
 
     while (text < stop) {
-        const SkGlyph& glyph = glyphCacheProc(cache, &text, 0, 0);
+        const SkGlyph& glyph = glyphCacheProc(cache.get(), &text, 0, 0);
         if (glyph.fWidth) {
             const SkPath* path = cache->findPath(glyph);
             if (path) {
@@ -1656,18 +1658,17 @@ void SkDraw::drawPosText(const char text[], size_t byteLength,
         return;
     }
 
-    SkAutoGlyphCache       autoCache(paint, &fDevice->surfaceProps(), fMatrix);
-    SkGlyphCache*          cache = autoCache.getCache();
+    SkAutoGlyphCache cache(paint, &fDevice->surfaceProps(), this->fakeGamma(), fMatrix);
 
     // The Blitter Choose needs to be live while using the blitter below.
     SkAutoBlitterChoose    blitterChooser(fDst, *fMatrix, paint);
     SkAAClipBlitterWrapper wrapper(*fRC, blitterChooser.get());
-    DrawOneGlyph           drawOneGlyph(*this, paint, cache, wrapper.getBlitter());
+    DrawOneGlyph           drawOneGlyph(*this, paint, cache.get(), wrapper.getBlitter());
     SkPaint::Align         textAlignment = paint.getTextAlign();
 
     SkFindAndPlaceGlyph::ProcessPosText(
         paint.getTextEncoding(), text, byteLength,
-        offset, *fMatrix, pos, scalarsPerPosition, textAlignment, cache, drawOneGlyph);
+        offset, *fMatrix, pos, scalarsPerPosition, textAlignment, cache.get(), drawOneGlyph);
 }
 
 #if defined _WIN32 && _MSC_VER >= 1300