bindings: Use ExceptionMessages when an interface/callback conversion fails.

third_party/WebKit/Source/bindings/templates/callback_function.cpp.tmpl

 {% from 'utilities.cpp.tmpl' import v8_value_to_local_cpp_value %}
 {% filter format_blink_cpp_source_code %}
 
 {% include 'copyright_block.txt' %}
 
 #include "{{cpp_class}}.h"
 
 {% for filename in cpp_includes %}
 #include "{{filename}}"
 {% endfor %}
@@ skipping 64 matching lines @@
 
   {% if return_value %}
   {{v8_value_to_local_cpp_value(return_value) | indent(2)}}
   returnValue = cppValue;
   {% endif %}
   return true;
 }
 
 {{cpp_class}}* NativeValueTraits<{{cpp_class}}>::NativeValue(v8::Isolate* isolate, v8::Local<v8::Value> value, ExceptionState& exceptionState) {
   {{cpp_class}}* nativeValue = {{cpp_class}}::Create(ScriptState::Current(isolate), value);
-  if (!nativeValue)
-    exceptionState.ThrowTypeError("Unable to convert value to {{callback_function_name}}.");
+  if (!nativeValue) {
+    exceptionState.ThrowTypeError(ExceptionMessages::FailedToConvertJSValue(
+        "{{callback_function_name}}"));
+  }
   return nativeValue;
 }
 
 }  // namespace blink
 
 {% endfilter %}{# format_blink_cpp_source_code #}