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

components/autofill/content/renderer/form_autofill_util.cc

Index: components/autofill/content/renderer/form_autofill_util.cc
diff --git a/components/autofill/content/renderer/form_autofill_util.cc b/components/autofill/content/renderer/form_autofill_util.cc
index 51a2251258b73d0faf6bf61afbc8fec36b951d11..2fceb82dd78c93a3802d1a67c081bf2e41a1933f 100644
--- a/components/autofill/content/renderer/form_autofill_util.cc
+++ b/components/autofill/content/renderer/form_autofill_util.cc
@@ -16,6 +16,7 @@
 #include "components/autofill/core/common/autofill_data_validation.h"
 #include "components/autofill/core/common/autofill_regexes.h"
 #include "components/autofill/core/common/autofill_switches.h"
+#include "components/autofill/core/common/autofill_util.h"
 #include "components/autofill/core/common/form_data.h"
 #include "components/autofill/core/common/form_field_data.h"
 #include "third_party/WebKit/public/platform/WebString.h"
@@ -871,9 +872,7 @@ void PreviewFormField(const FormFieldData& data,
   if (is_initiating_node &&
       (IsTextInput(input_element) || IsTextAreaElement(*field))) {
     // Select the part of the text that the user didn't type.
-    int start = field->value().length();
-    int end = field->suggestedValue().length();
-    field->setSelectionRange(start, end);
+    PreviewSuggestion(data.value, field);
   }
 }
 
@@ -1534,4 +1533,14 @@ gfx::RectF GetScaledBoundingBox(float scale, WebElement* element) {
                     bounding_box.height() * scale);
 }
 
+void PreviewSuggestion(const base::string16& suggestion,
+                       WebFormControlElement* input_element) {
+  DCHECK(input_element);

[please use gerrit instead, 2015/06/29 22:06:28]

The rest of the code in this file does not DCHECK pointers before dereferencing
them. Let's be consistent and not DCHECK in your function either. No worries,
both DCHECK and dereference behave the same way (crash with a stack trace).

[Pritam Nikam, 2015/06/30 15:05:50]

Done.

+  input_element->setSelectionRange(
+      IsFeatureSubstringMatchEnabled()
+          ? autofill::GetTextSelectionStart(suggestion, input_element->value())

[please use gerrit instead, 2015/06/29 22:06:28]

Either use |suggestion| or input_element->suggestedValue() throughout the
function, but not both.

[Pritam Nikam, 2015/06/30 15:05:50]

Done.

+          : input_element->value().length(),
+      input_element->suggestedValue().length());
+}
+
 }  // namespace autofill