Password page analyzer fix.

This CL fixes typo password_inputs->explicit_password_inputs. Which in some rare situations
leads to crash.

Bug: 805892
Change-Id: Ibe76806154e7172a4d433d51ec92fb20ba0d900c
Reviewed-on: https://chromium-review.googlesource.com/893298Reviewed-by: Maxim Kolosovskiy <kolos@chromium.org>
Commit-Queue: Maxim Kolosovskiy <kolos@chromium.org>
Commit-Queue: Vadym Doroshenko <dvadym@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532870}

chrome/renderer/autofill/page_passwords_analyser_browsertest.cc

@@ -99,6 +99,13 @@ const char kInferredUsernameAutocompleteAttributes[] =
     "   <input type='password' autocomplete='new-password'>"
     "</form>";
 
+const char kPasswordFieldsWithAndWithoutAutocomplete[] =
+    "<form>"
+    "   <input type='password'>"
+    "   <input type='text'>"
+    "   <input type='password' autocomplete='current-password'>"
+    "</form>";
+
 const std::string AutocompleteSuggestionString(const std::string& suggestion) {
   return "Input elements should have autocomplete "
          "attributes (suggested: \"" +
@@ -254,4 +261,14 @@ TEST_F(PagePasswordsAnalyserTest, InferredUsernameAutocompleteAttributes) {
   RunTestCase();
 }
 
+TEST_F(PagePasswordsAnalyserTest, PasswordFieldWithAndWithoutAutocomplete) {
+  LoadTestCase(kPasswordFieldsWithAndWithoutAutocomplete);
+  Expect(
+      "Multiple forms should be contained in their own "
+      "form elements; break up complex forms into ones that represent a "
+      "single action:",
+      PageFormAnalyserLogger::kVerbose, {0});
+  RunTestCase();
+}
+
 }  // namespace autofill

components/autofill/content/renderer/page_passwords_analyser.cc

@@ -371,8 +371,9 @@ void AnalyseForm(const FormInputCollection& form_input_collection,
     } else {
       // By default (if the other heuristics fail), the first text field
       // preceding a password field will be considered the username field.
-      for (username_field_guess = password_inputs[0] - 1;;
+      for (username_field_guess = explicit_password_inputs[0] - 1;;
            --username_field_guess) {
+        DCHECK(username_field_guess < signature.size());
         if (signature[username_field_guess] == kTextFieldSignature)
           break;
       }