[Autofill/Autocomplete Feature] Substring matching instead of prefix matching.

components/autofill/content/browser/content_autofill_driver_unittest.cc

Index: components/autofill/content/browser/content_autofill_driver_unittest.cc
diff --git a/components/autofill/content/browser/content_autofill_driver_unittest.cc b/components/autofill/content/browser/content_autofill_driver_unittest.cc
index 31ffba8b15d569ff8e0a7682bb13eadc9f0b5019..18f08ad362a20940ec8bf94f8ce7a3c0a6201515 100644
--- a/components/autofill/content/browser/content_autofill_driver_unittest.cc
+++ b/components/autofill/content/browser/content_autofill_driver_unittest.cc
@@ -161,10 +161,17 @@ class ContentAutofillDriverTest : public content::RenderViewHostTestHarness {
         if (!AutofillMsg_FillFieldWithValue::Read(message, &autofill_param))
           return false;
         break;
-      case AutofillMsg_PreviewFieldWithValue::ID:
-        if (!AutofillMsg_PreviewFieldWithValue::Read(message, &autofill_param))
+      case AutofillMsg_PreviewFieldWithValue::ID: {
+        base::Tuple<base::string16, int> autofill_param_preview;
+        if (AutofillMsg_PreviewFieldWithValue::Read(message,
+                                                    &autofill_param_preview)) {
+          if (value)
+            *value = base::get<0>(autofill_param);
+          process()->sink().ClearMessages();
+          return true;
+        }
           return false;
-        break;
+      } break;
       case AutofillMsg_AcceptDataListSuggestion::ID:
         if (!AutofillMsg_AcceptDataListSuggestion::Read(message,
                                                         &autofill_param))
@@ -313,7 +320,8 @@ TEST_F(ContentAutofillDriverTest, FillFieldWithValue) {
 TEST_F(ContentAutofillDriverTest, PreviewFieldWithValue) {
   base::string16 input_value(base::ASCIIToUTF16("barqux"));
   base::string16 output_value;
-  driver_->RendererShouldPreviewFieldWithValue(input_value);
+  size_t match_start = 0;
+  driver_->RendererShouldPreviewFieldWithValue(input_value, match_start);
   EXPECT_TRUE(GetString16FromMessageWithID(
       AutofillMsg_PreviewFieldWithValue::ID,
       &output_value));