Clean up of GLES2 Command Decoder by moving some of the error state into a separate class.

gpu/command_buffer/service/context_state.h

Index: gpu/command_buffer/service/context_state.h
diff --git a/gpu/command_buffer/service/context_state.h b/gpu/command_buffer/service/context_state.h
index f4e0f4c01ad5a169e98e9e4a42b6b021209baff0..5227126c74d12d25aeb5d6061f7dfb638cca3f38 100644
--- a/gpu/command_buffer/service/context_state.h
+++ b/gpu/command_buffer/service/context_state.h
@@ -9,6 +9,7 @@
 
 #include <vector>
 #include "base/logging.h"
+#include "gpu/command_buffer/service/error_state.h"
 #include "gpu/command_buffer/service/gl_utils.h"
 #include "gpu/command_buffer/service/query_manager.h"
 #include "gpu/command_buffer/service/texture_manager.h"
@@ -91,7 +92,7 @@ struct Vec4 {
 };
 
 struct GPU_EXPORT ContextState {
-  explicit ContextState(FeatureInfo* feature_info);
+  ContextState(FeatureInfo* feature_info, Logger* logger);
   ~ContextState();
 
   void Initialize();
@@ -115,6 +116,8 @@ struct GPU_EXPORT ContextState {
       GLenum pname, GLfloat* params, GLsizei* num_written) const;
   bool GetEnabled(GLenum cap) const;
 
+  ErrorState* GetErrorState();
+
   #include "gpu/command_buffer/service/context_state_autogen.h"
 
   EnableFlags enable_flags;
@@ -161,8 +164,10 @@ struct GPU_EXPORT ContextState {
   bool pack_reverse_row_order;
 
   mutable bool fbo_binding_for_scissor_workaround_dirty_;
-
   FeatureInfo* feature_info_;
+
+ private:
+  ErrorStateImpl error_state_;
 };
 
 }  // namespace gles2