diff --git a/dom/base/nsPlainTextSerializer.cpp b/dom/base/nsPlainTextSerializer.cpp
index 198e82d1eace..8dbb840162b2 100644
--- a/dom/base/nsPlainTextSerializer.cpp
+++ b/dom/base/nsPlainTextSerializer.cpp
@@ -684,8 +684,6 @@ nsresult nsPlainTextSerializer::DoOpenContainer(const nsAtom* aTag) {
     // Trigger on the presence of a "pre-wrap" in the
     // style attribute. That's a very simplistic way to do
     // it, but better than nothing.
-    // Also set mWrapColumn to the value given there
-    // (which arguably we should only do if told to do so).
     nsAutoString style;
     int32_t whitespace;
     if (NS_SUCCEEDED(GetAttributeValue(nsGkAtoms::style, style)) &&
@@ -695,28 +693,6 @@ nsresult nsPlainTextSerializer::DoOpenContainer(const nsAtom* aTag) {
         printf("Set mPreFormattedMail based on style pre-wrap\n");
 #endif
         mPreFormattedMail = true;
-        int32_t widthOffset = style.Find("width:");
-        if (widthOffset >= 0) {
-          // We have to search for the ch before the semicolon,
-          // not for the semicolon itself, because nsString::ToInteger()
-          // considers 'c' to be a valid numeric char (even if radix=10)
-          // but then gets confused if it sees it next to the number
-          // when the radix specified was 10, and returns an error code.
-          int32_t semiOffset = style.Find("ch", false, widthOffset + 6);
-          int32_t length = (semiOffset > 0 ? semiOffset - widthOffset - 6
-                                           : style.Length() - widthOffset);
-          nsAutoString widthstr;
-          style.Mid(widthstr, widthOffset + 6, length);
-          nsresult err;
-          int32_t col = widthstr.ToInteger(&err);
-
-          if (NS_SUCCEEDED(err)) {
-            mWrapColumn = (uint32_t)col;
-#ifdef DEBUG_preformatted
-            printf("Set wrap column to %d based on style\n", mWrapColumn);
-#endif
-          }
-        }
       } else if (kNotFound != style.Find("pre", true, whitespace)) {
 #ifdef DEBUG_preformatted
         printf("Set mPreFormattedMail based on style pre\n");
diff --git a/dom/base/test/gtest/TestPlainTextSerializer.cpp b/dom/base/test/gtest/TestPlainTextSerializer.cpp
index ef2e37e26397..8ae8ec7c2cfb 100644
--- a/dom/base/test/gtest/TestPlainTextSerializer.cpp
+++ b/dom/base/test/gtest/TestPlainTextSerializer.cpp
@@ -12,9 +12,11 @@
 #include "nsCRT.h"
 #include "nsIParserUtils.h"
 
-void ConvertBufToPlainText(nsString& aConBuf, int aFlag) {
+const uint32_t kDefaultWrapColumn = 72;
+
+void ConvertBufToPlainText(nsString& aConBuf, int aFlag, uint32_t aWrapColumn) {
   nsCOMPtr<nsIParserUtils> utils = do_GetService(NS_PARSERUTILS_CONTRACTID);
-  utils->ConvertToPlainText(aConBuf, aFlag, 72, aConBuf);
+  utils->ConvertToPlainText(aConBuf, aFlag, aWrapColumn, aConBuf);
 }
 
 // Test for ASCII with format=flowed; delsp=yes
@@ -30,11 +32,13 @@ TEST(PlainTextSerializer, ASCIIWithFlowedDelSp)
       "Firefox Firefox Firefox Firefox"
       "</body></html>");
 
-  ConvertBufToPlainText(test, nsIDocumentEncoder::OutputFormatted |
-                                  nsIDocumentEncoder::OutputCRLineBreak |
-                                  nsIDocumentEncoder::OutputLFLineBreak |
-                                  nsIDocumentEncoder::OutputFormatFlowed |
-                                  nsIDocumentEncoder::OutputFormatDelSp);
+  ConvertBufToPlainText(test,
+                        nsIDocumentEncoder::OutputFormatted |
+                            nsIDocumentEncoder::OutputCRLineBreak |
+                            nsIDocumentEncoder::OutputLFLineBreak |
+                            nsIDocumentEncoder::OutputFormatFlowed |
+                            nsIDocumentEncoder::OutputFormatDelSp,
+                        kDefaultWrapColumn);
 
   // create result case
   result.AssignLiteral(
@@ -59,11 +63,13 @@ TEST(PlainTextSerializer, CJKWithFlowedDelSp)
   }
   test.AppendLiteral("</body></html>");
 
-  ConvertBufToPlainText(test, nsIDocumentEncoder::OutputFormatted |
-                                  nsIDocumentEncoder::OutputCRLineBreak |
-                                  nsIDocumentEncoder::OutputLFLineBreak |
-                                  nsIDocumentEncoder::OutputFormatFlowed |
-                                  nsIDocumentEncoder::OutputFormatDelSp);
+  ConvertBufToPlainText(test,
+                        nsIDocumentEncoder::OutputFormatted |
+                            nsIDocumentEncoder::OutputCRLineBreak |
+                            nsIDocumentEncoder::OutputLFLineBreak |
+                            nsIDocumentEncoder::OutputFormatFlowed |
+                            nsIDocumentEncoder::OutputFormatDelSp,
+                        kDefaultWrapColumn);
 
   // create result case
   for (uint32_t i = 0; i < 36; i++) {
@@ -97,7 +103,8 @@ TEST(PlainTextSerializer, CJKWithDisallowLineBreaking)
                             nsIDocumentEncoder::OutputCRLineBreak |
                             nsIDocumentEncoder::OutputLFLineBreak |
                             nsIDocumentEncoder::OutputFormatFlowed |
-                            nsIDocumentEncoder::OutputDisallowLineBreaking);
+                            nsIDocumentEncoder::OutputDisallowLineBreaking,
+                        kDefaultWrapColumn);
 
   // create result case
   for (uint32_t i = 0; i < 400; i++) {
@@ -125,10 +132,12 @@ TEST(PlainTextSerializer, PreformatFlowedQuotes)
       "&gt;&gt; Firefox Firefox Firefox Firefox<br>"
       "</span></body></html>");
 
-  ConvertBufToPlainText(test, nsIDocumentEncoder::OutputFormatted |
-                                  nsIDocumentEncoder::OutputCRLineBreak |
-                                  nsIDocumentEncoder::OutputLFLineBreak |
-                                  nsIDocumentEncoder::OutputFormatFlowed);
+  ConvertBufToPlainText(test,
+                        nsIDocumentEncoder::OutputFormatted |
+                            nsIDocumentEncoder::OutputCRLineBreak |
+                            nsIDocumentEncoder::OutputLFLineBreak |
+                            nsIDocumentEncoder::OutputFormatFlowed,
+                        kDefaultWrapColumn);
 
   // create result case
   result.AssignLiteral(
@@ -151,7 +160,7 @@ TEST(PlainTextSerializer, PrettyPrintedHtml)
                      "  first<br>" NS_LINEBREAK "  second<br>" NS_LINEBREAK
                      "</body>" NS_LINEBREAK "</html>");
 
-  ConvertBufToPlainText(test, 0);
+  ConvertBufToPlainText(test, 0, kDefaultWrapColumn);
   ASSERT_TRUE(test.EqualsLiteral("first" NS_LINEBREAK "second" NS_LINEBREAK))
   << "Wrong prettyprinted html to text serialization";
 }
@@ -164,7 +173,7 @@ TEST(PlainTextSerializer, PreElement)
                      "  second" NS_LINEBREAK "</pre>" NS_LINEBREAK
                      "</body>" NS_LINEBREAK "</html>");
 
-  ConvertBufToPlainText(test, 0);
+  ConvertBufToPlainText(test, 0, kDefaultWrapColumn);
   ASSERT_TRUE(test.EqualsLiteral("  first" NS_LINEBREAK
                                  "  second" NS_LINEBREAK NS_LINEBREAK))
   << "Wrong prettyprinted html to text serialization";
@@ -179,7 +188,7 @@ TEST(PlainTextSerializer, BlockElement)
                      "  second" NS_LINEBREAK "</div>" NS_LINEBREAK
                      "</body>" NS_LINEBREAK "</html>");
 
-  ConvertBufToPlainText(test, 0);
+  ConvertBufToPlainText(test, 0, kDefaultWrapColumn);
   ASSERT_TRUE(test.EqualsLiteral("first" NS_LINEBREAK "second" NS_LINEBREAK))
   << "Wrong prettyprinted html to text serialization";
 }
@@ -188,14 +197,15 @@ TEST(PlainTextSerializer, PreWrapElementForThunderbird)
 {
   // This test examines the magic pre-wrap setup that Thunderbird relies on.
   nsString test;
-  test.AppendLiteral(
-      "<html>" NS_LINEBREAK
-      "<body style=\"white-space: pre-wrap; width: 10ch;\">" NS_LINEBREAK
-      "<pre>" NS_LINEBREAK "  first line is too long" NS_LINEBREAK
-      "  second line is even loooonger  " NS_LINEBREAK "</pre>" NS_LINEBREAK
-      "</body>" NS_LINEBREAK "</html>");
+  test.AppendLiteral("<html>" NS_LINEBREAK
+                     "<body style=\"white-space: pre-wrap;\">" NS_LINEBREAK
+                     "<pre>" NS_LINEBREAK
+                     "  first line is too long" NS_LINEBREAK
+                     "  second line is even loooonger  " NS_LINEBREAK
+                     "</pre>" NS_LINEBREAK "</body>" NS_LINEBREAK "</html>");
 
-  ConvertBufToPlainText(test, nsIDocumentEncoder::OutputWrap);
+  const uint32_t wrapColumn = 10;
+  ConvertBufToPlainText(test, nsIDocumentEncoder::OutputWrap, wrapColumn);
   // "\n\n  first\nline is\ntoo long\n  second\nline is\neven\nloooonger\n\n\n"
   ASSERT_TRUE(test.EqualsLiteral(
       NS_LINEBREAK NS_LINEBREAK
@@ -211,7 +221,7 @@ TEST(PlainTextSerializer, Simple)
   test.AppendLiteral(
       "<html><base>base</base><head><span>span</span></head>"
       "<body>body</body></html>");
-  ConvertBufToPlainText(test, 0);
+  ConvertBufToPlainText(test, 0, kDefaultWrapColumn);
   ASSERT_TRUE(test.EqualsLiteral("basespanbody"))
   << "Wrong html to text serialization";
 }