--- a/dom/canvas/WebGLContext.cpp
+++ b/dom/canvas/WebGLContext.cpp
@@ -592,17 +592,19 @@ CreateGLWithEGL(const gl::SurfaceCaps& c
         gl = nullptr;
     }
 
     if (!gl) {
         if (out_failReason->Length()) {
             out_failReason->AppendLiteral("\n");
         }
         out_failReason->AppendLiteral("Error during EGL OpenGL init.");
-        *out_failureId = "FEATURE_FAILURE_WEBGL_EGL_INIT";
+        if (out_failureId->IsEmpty()) {
+            *out_failureId = "FEATURE_FAILURE_WEBGL_EGL_INIT";
+        }
         return nullptr;
     }
 
     return gl.forget();
 }
 
 static already_AddRefed<GLContext>
 CreateGLWithANGLE(const gl::SurfaceCaps& caps, gl::CreateContextFlags flags,
@@ -616,17 +618,19 @@ CreateGLWithANGLE(const gl::SurfaceCaps&
         gl = nullptr;
     }
 
     if (!gl) {
         if (out_failReason->Length()) {
             out_failReason->AppendLiteral("\n");
         }
         out_failReason->AppendLiteral("Error during ANGLE OpenGL init.");
-        *out_failureId = "FEATURE_FAILURE_WEBGL_ANGLE_INIT";
+        if (out_failureId->IsEmpty()) {
+            *out_failureId = "FEATURE_FAILURE_WEBGL_ANGLE_INIT";
+        }
         return nullptr;
     }
 
     return gl.forget();
 }
 
 static already_AddRefed<gl::GLContext>
 CreateGLWithDefault(const gl::SurfaceCaps& caps, gl::CreateContextFlags flags,
@@ -654,17 +658,19 @@ CreateGLWithDefault(const gl::SurfaceCap
         gl = nullptr;
     }
 
     if (!gl) {
         if (out_failReason->Length()) {
             out_failReason->AppendASCII("\n");
         }
         out_failReason->AppendASCII("Error during native OpenGL init.");
-        *out_failureId = "FEATURE_FAILURE_WEBGL_DEFAULT_INIT";
+        if (out_failureId->IsEmpty()) {
+            *out_failureId = "FEATURE_FAILURE_WEBGL_DEFAULT_INIT";
+        }
         return nullptr;
     }
 
     return gl.forget();
 }
 
 ////////////////////////////////////////