[Autofill] Remove datalist flash when there is an existing entry.

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 f15a5806089307374c129c07574cdb94b8797764..4ca1c12f0697bef91ed7423e34c20286322a862c 100644
--- a/components/autofill/content/renderer/autofill_agent.cc
+++ b/components/autofill/content/renderer/autofill_agent.cc
@@ -78,26 +78,25 @@ namespace {
 // Gets all the data list values (with corresponding label) for the given
 // element.
 void GetDataListSuggestions(const WebInputElement& element,
-                            bool ignore_current_value,
                             std::vector<base::string16>* values,
                             std::vector<base::string16>* labels) {
   WebElementCollection options = element.dataListOptions();
   if (options.isNull())
     return;
 
-  base::string16 prefix;
-  if (!ignore_current_value) {
-    prefix = element.editingValue();
-    if (element.isMultiple() && element.isEmailField()) {
-      const base::char16 comma[2] = { ',', 0 };
-      std::vector<base::string16> parts = base::SplitString(
-          prefix, comma, base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
-      if (parts.size() > 0) {
-        base::TrimWhitespace(parts[parts.size() - 1], base::TRIM_LEADING,
-                             &prefix);
-      }
+  // If the field accepts multiple email addresses, filter only on the last one.
+  base::string16 prefix = element.editingValue();
+  if (element.isMultiple() && element.isEmailField()) {
+    const base::char16 comma[2] = { ',', 0 };
+    std::vector<base::string16> parts = base::SplitString(
+        prefix, comma, base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);

[vabr (Chromium), 2015/11/19 16:31:20]

optional:
comma -> ASCIITOUTF16(",")

[Mathieu, 2015/11/19 16:59:42]

Done.

+    if (parts.size() > 0) {

[vabr (Chromium), 2015/11/19 16:31:20]

optional: !parts.empty()

(This is similar to using .count() for checking whether there is an element,
which I mentioned in the other CL.)

[Evan Stade, 2015/11/19 16:45:12]

I don't see how it's similar to that one, because there's no extra work being
done here. But I agree .empty is more readable.

[vabr (Chromium), 2015/11/19 16:50:24]

Sorry that I was not clear. I meant using .empty() instead of .size() for
emptiness it as a general practice: There is no extra work for this particular
container (vector), but were it a linked list, for example, there would be extra
work. And .empty() will never be more work then .size().
But the readability yu point out is for me even more important. Good that
performance and readabilty are here aligned. :)

[Mathieu, 2015/11/19 16:59:42]

Done.

+      base::TrimWhitespace(parts[parts.size() - 1], base::TRIM_LEADING,
+                           &prefix);
     }
   }
+
+  // Prefix filtering.
   prefix = base::i18n::ToLower(prefix);
   for (WebOptionElement option = options.firstItem().to<WebOptionElement>();
        !option.isNull(); option = options.nextItem().to<WebOptionElement>()) {
@@ -739,7 +738,6 @@ void AutofillAgent::QueryAutofillSuggestions(
   if (input_element) {
     // Find the datalist values and send them to the browser process.
     GetDataListSuggestions(*input_element,
-                           datalist_only,
                            &data_list_values,
                            &data_list_labels);
     TrimStringVectorForIPC(&data_list_values);