Bring back sRGB-write-control as a caps bit.

src/gpu/gl/GrGLGpu.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 "GrGLGpu.h"
 #include "GrGLBuffer.h"
 #include "GrGLGLSL.h"
@@ skipping 2621 matching lines @@
             GL_CALL_RET(status, CheckFramebufferStatus(GR_GL_FRAMEBUFFER));
             if (status != GR_GL_FRAMEBUFFER_COMPLETE) {
                 SkDebugf("GrGLGpu::flushRenderTarget glCheckFramebufferStatus %x\n", status);
             }
         }
 #endif
         fHWBoundRenderTargetUniqueID = rtID;
         this->flushViewport(target->getViewport());
     }
 
-    if (this->glCaps().srgbSupport()) {
+    if (this->glCaps().srgbWriteControl()) {
         bool enableSRGBWrite = GrPixelConfigIsSRGB(target->config()) && !disableSRGB;
         if (enableSRGBWrite && kYes_TriState != fHWSRGBFramebuffer) {
             GL_CALL(Enable(GR_GL_FRAMEBUFFER_SRGB));
             fHWSRGBFramebuffer = kYes_TriState;
         } else if (!enableSRGBWrite && kNo_TriState != fHWSRGBFramebuffer) {
             GL_CALL(Disable(GR_GL_FRAMEBUFFER_SRGB));
             fHWSRGBFramebuffer = kNo_TriState;
         }
     }
 
@@ skipping 1593 matching lines @@
         if (GR_GL_TEXTURE_EXTERNAL == glTexture->target() ||
             GR_GL_TEXTURE_RECTANGLE == glTexture->target()) {
             copyParams->fFilter = GrTextureParams::kNone_FilterMode;
             copyParams->fWidth = texture->width();
             copyParams->fHeight = texture->height();
             return true;
         }
     }
     return false;
 }