--- a/dom/canvas/WebGLContext.cpp
+++ b/dom/canvas/WebGLContext.cpp
@@ -838,24 +838,25 @@ WebGLContext::SetDimensions(int32_t sign
     // TODO: When we have software webgl support we should use that instead.
     disabled |= gfxPlatform::InSafeMode();
 
     if (disabled) {
         GenerateWarning("WebGL creation is disabled, and so disallowed here.");
         return NS_ERROR_FAILURE;
     }
 
-    nsCOMPtr<nsIGfxInfo> gfxInfo = services::GetGfxInfo();
-    bool failIfMajorPerformanceCaveat =
-                    !gfxPrefs::WebGLDisableFailIfMajorPerformanceCaveat() &&
-                    !HasAcceleratedLayers(gfxInfo);
-    if (failIfMajorPerformanceCaveat) {
-        dom::Nullable<dom::WebGLContextAttributes> contextAttributes;
-        this->GetContextAttributes(contextAttributes);
-        if (contextAttributes.Value().mFailIfMajorPerformanceCaveat) {
+    bool failIfPerfCaveat = mOptions.failIfMajorPerformanceCaveat;
+    if (gfxPrefs::WebGLDisableFailIfMajorPerformanceCaveat())
+        failIfPerfCaveat = false;
+
+    if (failIfPerfCaveat) {
+        nsCOMPtr<nsIGfxInfo> gfxInfo = services::GetGfxInfo();
+        if (!HasAcceleratedLayers(gfxInfo)) {
+            GenerateWarning("failIfMajorPerformanceCaveat: Compositor is not"
+                            " hardware-accelerated.");
             return NS_ERROR_FAILURE;
         }
     }
 
     // Alright, now let's start trying.
     bool forceEnabled = gfxPrefs::WebGLForceEnabled();
     ScopedGfxFeatureReporter reporter("WebGL", forceEnabled);