backout c3f1ab75ea51 (bug 421436) for regressing bug 439462

layout/forms/nsTextControlFrame.cpp

@@ -184,6 +184,12 @@ nsTextControlFrame::CalcIntrinsicSize(nsRenderingContext* aRenderingContext,
     }
     // Now add the extra padding on (so that small input sizes work well)
     aIntrinsicSize.width += internalPadding;
+  } else {
+    // This is to account for the anonymous <br> having a 1 twip width
+    // in Full Standards mode, see BRFrame::Reflow and bug 228752.
+    if (PresContext()->CompatibilityMode() == eCompatibility_FullStandards) {
+      aIntrinsicSize.width += 1;
+    }
   }
 
   // Increment width with cols * letter-spacing.