Add confidence to AutocompleteMatch.

chrome/browser/autocomplete/autocomplete_edit.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/autocomplete/autocomplete_edit.h"
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/metrics/histogram.h"
@@ skipping 186 matching lines @@
 
   FinalizeInstantQuery(view_->GetText(), suggestion, skip_inline_autocomplete);
   return true;
 }
 
 bool AutocompleteEditModel::AcceptCurrentInstantPreview() {
   return InstantController::CommitIfCurrent(controller_->GetInstant());
 }
 
 void AutocompleteEditModel::OnChanged() {
+  UMA_HISTOGRAM_COUNTS_100("Autocomplete.Confidence",
+                           CurrentMatch().confidence * 100);
   InstantController* instant = controller_->GetInstant();
   string16 suggested_text;
   TabContentsWrapper* tab = controller_->GetTabContentsWrapper();
   bool might_support_instant = false;
   if (!in_revert_ && tab) {
     if (instant) {
       if (user_input_in_progress() && popup_->IsOpen()) {
         AutocompleteMatch current_match = CurrentMatch();
         if (current_match.destination_url == PermanentURL()) {
           // The destination is the same as the current url. This typically
@@ skipping 793 matching lines @@
 //  static
 bool AutocompleteEditModel::IsSpaceCharForAcceptingKeyword(wchar_t c) {
   switch (c) {
     case 0x0020:  // Space
     case 0x3000:  // Ideographic Space
       return true;
     default:
       return false;
   }
 }