Fix more disabled MSVC warnings, base/ edition.

base/metrics/field_trial_unittest.cc

 // Copyright (c) 2012 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 "base/metrics/field_trial.h"
 
 #include "base/message_loop/message_loop.h"
 #include "base/rand_util.h"
 #include "base/run_loop.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 96 matching lines @@
   // Note: FieldTrialList should delete the objects at shutdown.
 }
 
 TEST_F(FieldTrialTest, AbsoluteProbabilities) {
   char always_true[] = " always true";
   char default_always_true[] = " default always true";
   char always_false[] = " always false";
   char default_always_false[] = " default always false";
   for (int i = 1; i < 250; ++i) {
     // Try lots of names, by changing the first character of the name.
-    always_true[0] = i;
-    default_always_true[0] = i;
-    always_false[0] = i;
-    default_always_false[0] = i;
+    char c = static_cast<char>(i);
+    always_true[0] = c;
+    default_always_true[0] = c;
+    always_false[0] = c;
+    default_always_false[0] = c;
 
     scoped_refptr<FieldTrial> trial_true =
         CreateFieldTrial(always_true, 10, default_always_true, NULL);
     const std::string winner = "TheWinner";
     int winner_group = trial_true->AppendGroup(winner, 10);
 
     EXPECT_EQ(winner_group, trial_true->group());
     EXPECT_EQ(winner, trial_true->group_name());
 
     scoped_refptr<FieldTrial> trial_false =
@@ skipping 52 matching lines @@
   EXPECT_TRUE(second_winner);
   EXPECT_TRUE(first_winner);
 }
 
 TEST_F(FieldTrialTest, MiddleProbabilities) {
   char name[] = " same name";
   char default_group_name[] = " default same name";
   bool false_event_seen = false;
   bool true_event_seen = false;
   for (int i = 1; i < 250; ++i) {
-    name[0] = i;
-    default_group_name[0] = i;
+    char c = static_cast<char>(i);
+    name[0] = c;
+    default_group_name[0] = c;
     scoped_refptr<FieldTrial> trial =
         CreateFieldTrial(name, 10, default_group_name, NULL);
     int might_win = trial->AppendGroup("MightWin", 5);
 
     if (trial->group() == might_win) {
       true_event_seen = true;
     } else {
       false_event_seen = true;
     }
     if (false_event_seen && true_event_seen)
@@ skipping 779 matching lines @@
     EXPECT_TRUE(active_groups.empty());
 
     // The trial shouldn't be listed in the |StatesToString()| result.
     std::string states;
     FieldTrialList::StatesToString(&states);
     EXPECT_TRUE(states.empty());
   }
 }
 
 }  // namespace base