--- a/gfx/layers/wr/WebRenderBridgeParent.cpp
+++ b/gfx/layers/wr/WebRenderBridgeParent.cpp
@@ -59,16 +59,25 @@ bool is_glcontext_egl(void* glcontext_pt
   return glcontext->GetContextType() == mozilla::gl::GLContextType::EGL;
 }
 
 bool gfx_use_wrench()
 {
   return gfxEnv::EnableWebRenderRecording();
 }
 
+const char* gfx_wr_resource_path_override()
+{
+  const char* resourcePath = PR_GetEnv("WR_RESOURCE_PATH");
+  if (!resourcePath || resourcePath[0] == '\0') {
+    return nullptr;
+  }
+  return resourcePath;
+}
+
 void gfx_critical_note(const char* msg)
 {
   gfxCriticalNote << msg;
 }
 
 void* get_proc_address_from_glcontext(void* glcontext_ptr, const char* procname)
 {
   MOZ_ASSERT(glcontext_ptr);

--- a/gfx/webrender_bindings/src/bindings.rs
+++ b/gfx/webrender_bindings/src/bindings.rs
@@ -1,9 +1,9 @@
-use std::ffi::CString;
+use std::ffi::{CStr, CString};
 use std::{mem, slice};
 use std::path::PathBuf;
 use std::ptr;
 use std::sync::Arc;
 use std::os::raw::{c_void, c_char, c_float};
 use gleam::gl;
 
 use webrender_api::*;
@@ -410,16 +410,17 @@ extern "C" {
     fn is_in_main_thread() -> bool;
     fn is_glcontext_egl(glcontext_ptr: *mut c_void) -> bool;
     // Enables binary recording that can be used with `wrench replay`
     // Outputs a wr-record-*.bin file for each window that is shown
     // Note: wrench will panic if external images are used, they can
     // be disabled in WebRenderBridgeParent::ProcessWebRenderCommands
     // by commenting out the path that adds an external image ID
     fn gfx_use_wrench() -> bool;
+    fn gfx_wr_resource_path_override() -> *const c_char;
     fn gfx_critical_note(msg: *const c_char);
 }
 
 struct CppNotifier {
     window_id: WrWindowId,
 }
 
 unsafe impl Send for CppNotifier {}
@@ -639,16 +640,27 @@ pub extern "C" fn wr_window_new(window_i
 
     let opts = RendererOptions {
         enable_aa: true,
         enable_subpixel_aa: true,
         recorder: recorder,
         blob_image_renderer: Some(Box::new(Moz2dImageRenderer::new(workers.clone()))),
         workers: Some(workers.clone()),
         enable_render_on_scroll: false,
+        resource_override_path: unsafe {
+            let override_charptr = gfx_wr_resource_path_override();
+            if override_charptr.is_null() {
+                None
+            } else {
+                match CStr::from_ptr(override_charptr).to_str() {
+                    Ok(override_str) => Some(PathBuf::from(override_str)),
+                    _ => None
+                }
+            }
+        },
         ..Default::default()
     };
 
     let (renderer, sender) = match Renderer::new(gl, opts) {
         Ok((renderer, sender)) => (renderer, sender),
         Err(e) => {
             println!(" Failed to create a Renderer: {:?}", e);
             let msg = CString::new(format!("wr_window_new: {:?}", e)).unwrap();

--- a/gfx/webrender_bindings/webrender_ffi.h
+++ b/gfx/webrender_bindings/webrender_ffi.h
@@ -16,16 +16,17 @@ extern "C" {
 // Functions invoked from Rust code
 // ----
 
 bool is_in_compositor_thread();
 bool is_in_main_thread();
 bool is_in_render_thread();
 bool is_glcontext_egl(void* glcontext_ptr);
 bool gfx_use_wrench();
+const char* gfx_wr_resource_path_override();
 void gfx_critical_note(const char* msg);
 void* get_proc_address_from_glcontext(void* glcontext_ptr, const char* procname);
 
 } // extern "C"
 
 // Some useful defines to stub out webrender binding functions for when we
 // build gecko without webrender. We try to tell the compiler these functions
 // are unreachable in that case, but VC++ emits a warning if it finds any

--- a/gfx/webrender_bindings/webrender_ffi_generated.h
+++ b/gfx/webrender_bindings/webrender_ffi_generated.h
@@ -1,13 +1,13 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-/* Generated with cbindgen:0.1.23 */
+/* Generated with cbindgen:0.1.25 */
 
 /* DO NOT MODIFY THIS MANUALLY! This file was generated using cbindgen.
  * To generate this file:
  *   1. Get the latest cbindgen using `cargo install --force cbindgen`
  *      a. Alternatively, you can clone `https://github.com/rlhunt/cbindgen` and use a tagged release
  *   2. Run `rustup run nightly cbindgen toolkit/library/rust/ --crate webrender_bindings -o gfx/webrender_bindings/webrender_ffi_generated.h`
  */
 
@@ -758,16 +758,18 @@ struct FontInstancePlatformOptions {
  *      a. Alternatively, you can clone `https://github.com/rlhunt/cbindgen` and use a tagged release
  *   2. Run `rustup run nightly cbindgen toolkit/library/rust/ --crate webrender_bindings -o gfx/webrender_bindings/webrender_ffi_generated.h`
  */
 
 extern void gfx_critical_note(const char *aMsg);
 
 extern bool gfx_use_wrench();
 
+extern const char *gfx_wr_resource_path_override();
+
 extern bool is_glcontext_egl(void *aGlcontextPtr);
 
 extern bool is_in_compositor_thread();
 
 extern bool is_in_main_thread();
 
 extern bool is_in_render_thread();