diff --git a/dom/canvas/ClientWebGLContext.cpp b/dom/canvas/ClientWebGLContext.cpp
index 7a8b19ad008fc..1f7a7330508df 100644
--- a/dom/canvas/ClientWebGLContext.cpp
+++ b/dom/canvas/ClientWebGLContext.cpp
@@ -4856,9 +4856,8 @@ void ClientWebGLContext::UniformData(const GLenum funcElemType,
   const auto begin =
       reinterpret_cast<const webgl::UniformDataVal*>(bytes.begin().get()) +
       elemOffset;
-  const auto range = Range{begin, availCount};
-  RunWithGCData<RPROC(UniformData)>(std::move(nogc), locId, transpose,
-                                    RawBuffer{range});
+  const auto range = Span{begin, availCount};
+  RunWithGCData<RPROC(UniformData)>(std::move(nogc), locId, transpose, range);
 }
 
 // -
diff --git a/dom/canvas/HostWebGLContext.h b/dom/canvas/HostWebGLContext.h
index a9e43fb60fd2a..cc385bc26a63f 100644
--- a/dom/canvas/HostWebGLContext.h
+++ b/dom/canvas/HostWebGLContext.h
@@ -603,8 +603,8 @@ class HostWebGLContext final : public SupportsWeakPtr {
   // ------------------------ Uniforms and attributes ------------------------
 
   void UniformData(uint32_t loc, bool transpose,
-                   const RawBuffer<webgl::UniformDataVal>& data) const {
-    mContext->UniformData(loc, transpose, data.Data());
+                   const Span<const webgl::UniformDataVal>& data) const {
+    mContext->UniformData(loc, transpose, data);
   }
 
   void VertexAttrib4T(GLuint index, const webgl::TypedQuad& data) const {
diff --git a/dom/canvas/QueueParamTraits.h b/dom/canvas/QueueParamTraits.h
index fbedcdea0bf59..fef59db7970ab 100644
--- a/dom/canvas/QueueParamTraits.h
+++ b/dom/canvas/QueueParamTraits.h
@@ -98,6 +98,10 @@ template <>
 struct BytesAlwaysValidT<webgl::UniformDataVal> {
   static constexpr bool value = true;
 };
+template <>
+struct BytesAlwaysValidT<const webgl::UniformDataVal> {
+  static constexpr bool value = true;
+};
 
 // -
 
diff --git a/dom/canvas/WebGLContext.h b/dom/canvas/WebGLContext.h
index cb87c9aed523c..dbaca23a39bb0 100644
--- a/dom/canvas/WebGLContext.h
+++ b/dom/canvas/WebGLContext.h
@@ -667,7 +667,7 @@ class WebGLContext : public VRefCounted, public SupportsWeakPtr {
   //////////////////////////
 
   void UniformData(uint32_t loc, bool transpose,
-                   const Range<const webgl::UniformDataVal>& data) const;
+                   const Span<const webgl::UniformDataVal>& data) const;
 
   ////////////////////////////////////
 
diff --git a/dom/canvas/WebGLContextGL.cpp b/dom/canvas/WebGLContextGL.cpp
index 7411cec02fd93..ef068c8999428 100644
--- a/dom/canvas/WebGLContextGL.cpp
+++ b/dom/canvas/WebGLContextGL.cpp
@@ -1280,7 +1280,7 @@ void WebGLContext::StencilOpSeparate(GLenum face, GLenum sfail, GLenum dpfail,
 
 void WebGLContext::UniformData(
     const uint32_t loc, const bool transpose,
-    const Range<const webgl::UniformDataVal>& data) const {
+    const Span<const webgl::UniformDataVal>& data) const {
   const FuncScope funcScope(*this, "uniform setter");
 
   if (!IsWebGL2() && transpose) {
@@ -1306,13 +1306,13 @@ void WebGLContext::UniformData(
 
   // -
 
-  const auto lengthInType = data.length();
+  const auto lengthInType = data.size();
   const auto elemCount = lengthInType / channels;
   if (elemCount > 1 && !validationInfo.isArray) {
     GenerateError(
         LOCAL_GL_INVALID_OPERATION,
         "(uniform %s) `values` length (%u) must exactly match size of %s.",
-        activeInfo.name.c_str(), lengthInType,
+        activeInfo.name.c_str(), (uint32_t)lengthInType,
         EnumString(activeInfo.elemType).c_str());
     return;
   }
@@ -1321,9 +1321,9 @@ void WebGLContext::UniformData(
 
   const auto& samplerInfo = locInfo->samplerInfo;
   if (samplerInfo) {
-    const auto idata = reinterpret_cast<const uint32_t*>(data.begin().get());
+    const auto idata = ReinterpretToSpan<const uint32_t>::From(data);
     const auto maxTexUnits = GLMaxTextureUnits();
-    for (const auto& val : Range<const uint32_t>(idata, elemCount)) {
+    for (const auto& val : idata) {
       if (val >= maxTexUnits) {
         ErrorInvalidValue(
             "This uniform location is a sampler, but %d"
@@ -1337,7 +1337,7 @@ void WebGLContext::UniformData(
   // -
 
   // This is a little galaxy-brain, sorry!
-  const auto ptr = static_cast<const void*>(data.begin().get());
+  const auto ptr = static_cast<const void*>(data.data());
   (*pfn)(*gl, static_cast<GLint>(loc), elemCount, transpose, ptr);
 
   // -
@@ -1345,12 +1345,12 @@ void WebGLContext::UniformData(
   if (samplerInfo) {
     auto& texUnits = samplerInfo->texUnits;
 
-    const auto srcBegin = reinterpret_cast<const uint32_t*>(data.begin().get());
+    const auto srcBegin = reinterpret_cast<const uint32_t*>(data.data());
     auto destIndex = locInfo->indexIntoUniform;
     if (destIndex < texUnits.length()) {
       // Only sample as many indexes as available tex units allow.
       const auto destCount = std::min(elemCount, texUnits.length() - destIndex);
-      for (const auto& val : Range<const uint32_t>(srcBegin, destCount)) {
+      for (const auto& val : Span<const uint32_t>(srcBegin, destCount)) {
         texUnits[destIndex] = AssertedCast<uint8_t>(val);
         destIndex += 1;
       }