gpu_tonemapper: Use individual EGL contexts.

- Use individual EGL contexts for each tone-mapping
  session.
- Having one context make multiple sessions serial, this
  helps in making this parallel when possible.
- Resolves error messages which happened when the context
  was deleted during mirroring.

Change-Id: Ia8738551b4189dccffb233320a9d69fcfd7f0118
Crs-fixed: 1115057
diff --git a/gpu_tonemapper/Tonemapper.h b/gpu_tonemapper/Tonemapper.h
index 0f9bd51..1d6f808 100644
--- a/gpu_tonemapper/Tonemapper.h
+++ b/gpu_tonemapper/Tonemapper.h
@@ -24,9 +24,11 @@
 #define TONEMAP_INVERSE 1
 
 #include "EGLImageWrapper.h"
+#include "engine.h"
 
 class Tonemapper {
  private:
+  void* engineContext;
   unsigned int tonemapTexture;
   unsigned int lutXformTexture;
   unsigned int programID;