Fix IOSurface synchronization issues

It appears that not only render targets, but also samplers that use
IOSurfaces require SwiftShader to perform synchronized draws,
otherwise it seems like using a shared IOSurface's CPU memory is
unsafe and can cause crashes in Layout Tests.

Bug chromium:846693

Change-Id: I0ce24700d34c657ac2447ceb2f6f837bfa3a9a58
Reviewed-on: https://swiftshader-review.googlesource.com/19288
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/src/Renderer/PixelProcessor.hpp b/src/Renderer/PixelProcessor.hpp
index 1954610..cea417d 100644
--- a/src/Renderer/PixelProcessor.hpp
+++ b/src/Renderer/PixelProcessor.hpp
@@ -242,6 +242,7 @@
 		void setMaxLevel(unsigned int sampler, int maxLevel);
 		void setMinLod(unsigned int sampler, float minLod);
 		void setMaxLod(unsigned int sampler, float maxLod);
+		void setSyncRequired(unsigned int sampler, bool isSincRequired);
 
 		void setWriteSRGB(bool sRGB);
 		void setDepthBufferEnable(bool depthBufferEnable);