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

components/autofill/content/renderer/autofill_agent.cc

Index: components/autofill/content/renderer/autofill_agent.cc
diff --git a/components/autofill/content/renderer/autofill_agent.cc b/components/autofill/content/renderer/autofill_agent.cc
index 31068330ae94793b6238892e9bc27b57bc7ca8d7..1f80d2ef6fcfa8fceb0c553484d147dbb365e2d6 100644
--- a/components/autofill/content/renderer/autofill_agent.cc
+++ b/components/autofill/content/renderer/autofill_agent.cc
@@ -19,6 +19,7 @@
 #include "components/autofill/core/common/autofill_constants.h"
 #include "components/autofill/core/common/autofill_data_validation.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_data_predictions.h"
 #include "components/autofill/core/common/form_field_data.h"
@@ -723,8 +724,16 @@ void AutofillAgent::PreviewFieldWithValue(const base::string16& value,
   was_query_node_autofilled_ = element_.isAutofilled();
   node->setSuggestedValue(value.substr(0, node->maxLength()));
   node->setAutofilled(true);
-  node->setSelectionRange(node->value().length(),
-                          node->suggestedValue().length());
+
+  if (IsFeatureSubstringMatchEnabled()) {
+    size_t start = autofill::GetTextSelectionStart(value, node->value());
+    if (start != base::string16::npos) {

[Evan Stade, 2015/04/27 19:25:21]

no curlies

[Pritam Nikam, 2015/04/28 14:45:55]

Done.

+      node->setSelectionRange(start, node->suggestedValue().length());
+    }
+  } else {
+    node->setSelectionRange(node->value().length(),
+                            node->suggestedValue().length());
+  }
 }
 
 void AutofillAgent::ProcessForms() {