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

gpu/command_buffer/service/test_helper.h

Index: gpu/command_buffer/service/test_helper.h
diff --git a/gpu/command_buffer/service/test_helper.h b/gpu/command_buffer/service/test_helper.h
index d04e9bddcc8e4802c67c5f5d6da5c9a4b52f97d4..41cb3aa1b27c80c3bedd2ee7f5a9dfaa3725f750 100644
--- a/gpu/command_buffer/service/test_helper.h
+++ b/gpu/command_buffer/service/test_helper.h
@@ -14,7 +14,7 @@ namespace gles2 {
 struct DisallowedFeatures;
 class Buffer;
 class BufferManager;
-class MockGLES2Decoder;
+class MockErrorState;
 class Texture;
 class TextureManager;
 
@@ -92,12 +92,12 @@ class TestHelper {
       GLuint service_id);
 
   static void DoBufferData(
-      ::gfx::MockGLInterface* gl, MockGLES2Decoder* decoder,
+      ::gfx::MockGLInterface* gl, MockErrorState* error_state,
       BufferManager* manager, Buffer* buffer, GLsizeiptr size, GLenum usage,
       const GLvoid* data, GLenum error);
 
   static void SetTexParameterWithExpectations(
-      ::gfx::MockGLInterface* gl, MockGLES2Decoder* decoder,
+      ::gfx::MockGLInterface* gl, MockErrorState* error_state,
       TextureManager* manager, Texture* texture,
       GLenum pname, GLint value, GLenum error);