Autofill: Fix broken DCHECK from r320637.

BUG=467429

Review URL: https://codereview.chromium.org/1018553002

Cr-Commit-Position: refs/heads/master@{#320841}

chrome/renderer/autofill/form_autofill_browsertest.cc

@@ -3126,6 +3126,10 @@ TEST_F(FormAutofillTest, LabelsInferredFromTableRow) {
   names.push_back(ASCIIToUTF16("phone3"));
   values.push_back(ASCIIToUTF16("7890"));
 
+  labels.push_back(ASCIIToUTF16("Credit Card Number"));
+  names.push_back(ASCIIToUTF16("ccnumber"));
+  values.push_back(ASCIIToUTF16("4444555544445555"));
+
   ExpectLabels(
       "<FORM name='TestForm' action='http://cnn.com' method='post'>"
       "<TABLE>"
@@ -3172,6 +3176,16 @@ TEST_F(FormAutofillTest, LabelsInferredFromTableRow) {
       "    </TD>"
       "  </TR>"
       "  <TR>"
+      "    <TH>"
+      "      Credit Card Number"
+      "    </TH>"
+      "  </TR>"
+      "  <TR>"
+      "    <TD>"
+      "      <INPUT type='text' name='ccnumber' value='4444555544445555'/>"
+      "    </TD>"
+      "  </TR>"
+      "  <TR>"
       "    <TD>"
       "      <INPUT type='submit' name='reply-send' value='Send'/>"
       "    </TD>"

components/autofill/content/renderer/form_autofill_util.cc

@@ -134,9 +134,9 @@ bool SatisfiesRequireAutocomplete(const WebInputElement& input_element) {
   return input_element.autoComplete();
 }
 
-// Returns the colspan for a <td>. Defaults to 1.
+// Returns the colspan for a <td> / <th>. Defaults to 1.
 size_t CalculateTableCellColumnSpan(const WebElement& element) {
-  DCHECK(element.hasHTMLTagName("td"));
+  DCHECK(element.hasHTMLTagName("td") || element.hasHTMLTagName("th"));
 
   size_t span = 1;
   if (element.hasAttribute("colspan")) {