Remove gl::Error.

Removes several TODOs. Only egl::Error remains.

Also slightly decreases binary size.

Bug: angleproject:2491
Change-Id: I3a9d1c22eb0884ca9e37362463fddd0083faf826
Reviewed-on: https://chromium-review.googlesource.com/c/1337462
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
diff --git a/src/libANGLE/renderer/null/ContextNULL.cpp b/src/libANGLE/renderer/null/ContextNULL.cpp
index 2983271..b9636e2 100644
--- a/src/libANGLE/renderer/null/ContextNULL.cpp
+++ b/src/libANGLE/renderer/null/ContextNULL.cpp
@@ -419,9 +419,7 @@
                               unsigned int line)
 {
     std::stringstream errorStream;
-    errorStream << "Internal OpenGL error: " << gl::FmtHex(errorCode) << ", in " << file << ", "
-                << function << ":" << line << ". " << message;
-
-    mErrors->handleError(gl::Error(errorCode, errorCode, errorStream.str()));
+    errorStream << "Internal NULL back-end error: " << message << ".";
+    mErrors->handleError(errorCode, errorStream.str().c_str(), file, function, line);
 }
 }  // namespace rx