Make GrGammaEffect have explicit sRGB modes, plus exponential mode.

src/gpu/GrContext.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrContext.h"
 #include "GrContextOptions.h"
 #include "GrDrawingManager.h"
@@ skipping 532 matching lines @@
     }
 
     SkSurfaceProps props(SkSurfaceProps::kGammaCorrect_Flag,
                          SkSurfaceProps::kLegacyFontHost_InitType);
     sk_sp<GrDrawContext> drawContext(this->drawContext(sk_ref_sp(dst), &props));
     if (!drawContext) {
         return false;
     }
 
     GrPaint paint;
-    if (SkScalarNearlyEqual(gamma, 1.0f)) {
-        paint.addColorTextureProcessor(src, GrCoordTransform::MakeDivByTextureWHMatrix(src));
-    } else {
-        SkAutoTUnref<const GrFragmentProcessor> fp;
-        fp.reset(GrGammaEffect::Create(src, gamma));
-        paint.addColorFragmentProcessor(fp);
+    paint.addColorTextureProcessor(src, GrCoordTransform::MakeDivByTextureWHMatrix(src));
+    if (!SkScalarNearlyEqual(gamma, 1.0f)) {
+        paint.addColorFragmentProcessor(GrGammaEffect::Create(gamma))->unref();
     }
     paint.setPorterDuffXPFactory(SkXfermode::kSrc_Mode);
     paint.setGammaCorrect(true);
 
     SkRect rect;
     src->getBoundsRect(&rect);
     drawContext->drawRect(GrClip::WideOpen(), paint, SkMatrix::I(), rect);
 
     this->flushSurfaceWrites(dst);
     return true;
@@ skipping 198 matching lines @@
     ASSERT_SINGLE_OWNER
     fResourceCache->setLimits(maxTextures, maxTextureBytes);
 }
 
 //////////////////////////////////////////////////////////////////////////////
 
 void GrContext::dumpMemoryStatistics(SkTraceMemoryDump* traceMemoryDump) const {
     ASSERT_SINGLE_OWNER
     fResourceCache->dumpMemoryStatistics(traceMemoryDump);
 }