--- a/dom/canvas/WebGLContext.cpp
+++ b/dom/canvas/WebGLContext.cpp
@@ -1962,17 +1962,17 @@ WebGLContext::TexSubImage2D(GLenum rawTe
     if (out_rv->Failed() || !data)
         return;
 
     gfx::IntSize size = data->GetSize();
     uint32_t byteLength = data->Stride() * size.height;
     TexSubImage2D_base(texImageTarget.get(), level, xoffset, yoffset, size.width,
                        size.height, data->Stride(), format, type, data->GetData(),
                        byteLength, js::Scalar::MaxTypedArrayViewType, srcFormat,
-                       mPixelStorePremultiplyAlpha);
+                       res.mIsPremultiplied);
 }
 
 size_t
 RoundUpToMultipleOf(size_t value, size_t multiple)
 {
     size_t overshoot = value + multiple - 1;
     return overshoot - (overshoot % multiple);
 }

--- a/dom/canvas/WebGLContext.h
+++ b/dom/canvas/WebGLContext.h
@@ -622,17 +622,17 @@ public:
             return;
 
         gfx::IntSize size = data->GetSize();
         uint32_t byteLength = data->Stride() * size.height;
         return TexImage2D_base(texImageTarget, level, internalFormat,
                                size.width, size.height, data->Stride(), 0,
                                format, type, data->GetData(), byteLength,
                                js::Scalar::MaxTypedArrayViewType, srcFormat,
-                               mPixelStorePremultiplyAlpha);
+                               res.mIsPremultiplied);
     }
 
     void TexParameterf(GLenum target, GLenum pname, GLfloat param) {
         TexParameter_base(target, pname, nullptr, &param);
     }
     void TexParameteri(GLenum target, GLenum pname, GLint param) {
         TexParameter_base(target, pname, &param, nullptr);
     }

--- a/dom/canvas/WebGLContextGL.cpp
+++ b/dom/canvas/WebGLContextGL.cpp
@@ -2487,30 +2487,16 @@ WebGLContext::SurfaceFromElementResultTo
     if (!res.mSourceSurface)
         return NS_OK;
     RefPtr<DataSourceSurface> data = res.mSourceSurface->GetDataSurface();
     if (!data) {
         // SurfaceFromElement lied!
         return NS_OK;
     }
 
-    if (!mPixelStorePremultiplyAlpha && res.mIsPremultiplied) {
-        switch (data->GetFormat()) {
-        case SurfaceFormat::B8G8R8X8:
-            // No alpha, so de-facto premult'd.
-            break;
-        case SurfaceFormat::B8G8R8A8:
-            data = gfxUtils::CreateUnpremultipliedDataSurface(data);
-            break;
-        default:
-            MOZ_ASSERT(false, "Format unsupported.");
-            break;
-        }
-    }
-
     // We disallow loading cross-domain images and videos that have not been validated
     // with CORS as WebGL textures. The reason for doing that is that timing
     // attacks on WebGL shaders are able to retrieve approximations of the
     // pixel values in WebGL textures; see bug 655987.
     //
     // To prevent a loophole where a Canvas2D would be used as a proxy to load
     // cross-domain textures, we also disallow loading textures from write-only
     // Canvas2D's.