Bug 1670232 - swgl: Add a get_name() function to ProgramImpl. r=lsalzman

This is very useful when used when printing timings of draw calls.

Differential Revision: https://phabricator.services.mozilla.com/D93115

gfx/wr/glsl-to-cxx/src/lib.rs

@@ -250,6 +250,7 @@ fn translate_shader(
             write!(state, " return this;\n}}\n");
             write!(state, "FragmentShaderImpl* get_fragment_shader() override {{\n");
             write!(state, " return this;\n}}\n");
+            write!(state, "const char* get_name() const override {{ return \"{}\"; }}\n", name);
             write!(state, "static ProgramImpl* loader() {{ return new {}_program; }}\n", name);
             write!(state, "}};\n\n");
         }

gfx/wr/swgl/src/program.h

@@ -23,6 +23,7 @@ struct ProgramImpl {
   virtual size_t interpolants_size() const = 0;
   virtual VertexShaderImpl* get_vertex_shader() = 0;
   virtual FragmentShaderImpl* get_fragment_shader() = 0;
+  virtual const char* get_name() const = 0;
 };
 
 typedef ProgramImpl* (*ProgramLoader)();