Fix more disabled MSVC warnings, base/ edition.

Mostly this fixes cases of "possible value truncation", usually by inserting
explicit typecasts.

BUG=81439
TEST=none

Review URL: https://codereview.chromium.org/596103002

Cr-Commit-Position: refs/heads/master@{#297723}

3 files changed, 15 insertions, 11 deletions

diff --git a/base/metrics/field_trial_unittest.cc b/base/metrics/field_trial_unittest.cc
index a6dee11..52ce8554 100644
--- a/base/metrics/field_trial_unittest.cc
+++ b/base/metrics/field_trial_unittest.cc
@@ -114,10 +114,11 @@ TEST_F(FieldTrialTest, AbsoluteProbabilities) {
   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);
@@ -190,8 +191,9 @@ TEST_F(FieldTrialTest, MiddleProbabilities) {
   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);
diff --git a/base/metrics/histogram.cc b/base/metrics/histogram.cc
index 6e30892..6bab0eb 100644
--- a/base/metrics/histogram.cc
+++ b/base/metrics/histogram.cc
@@ -128,8 +128,9 @@ HistogramBase* Histogram::FactoryTimeGet(const string& name,
                                          TimeDelta maximum,
                                          size_t bucket_count,
                                          int32 flags) {
-  return FactoryGet(name, minimum.InMilliseconds(), maximum.InMilliseconds(),
-                    bucket_count, flags);
+  return FactoryGet(name, static_cast<Sample>(minimum.InMilliseconds()),
+                    static_cast<Sample>(maximum.InMilliseconds()), bucket_count,
+                    flags);
 }
 
 // Calculate what range of values are held in each bucket.
@@ -528,8 +529,9 @@ HistogramBase* LinearHistogram::FactoryTimeGet(const string& name,
                                                TimeDelta maximum,
                                                size_t bucket_count,
                                                int32 flags) {
-  return FactoryGet(name, minimum.InMilliseconds(), maximum.InMilliseconds(),
-                    bucket_count, flags);
+  return FactoryGet(name, static_cast<Sample>(minimum.InMilliseconds()),
+                    static_cast<Sample>(maximum.InMilliseconds()), bucket_count,
+                    flags);
 }
 
 HistogramBase* LinearHistogram::FactoryGetWithRangeDescription(
diff --git a/base/metrics/histogram_base.cc b/base/metrics/histogram_base.cc
index 6e7e69e..f09c84e 100644
--- a/base/metrics/histogram_base.cc
+++ b/base/metrics/histogram_base.cc
@@ -109,7 +109,7 @@ void HistogramBase::WriteJSON(std::string* output) const {
   DictionaryValue root;
   root.SetString("name", histogram_name());
   root.SetInteger("count", count);
-  root.SetDouble("sum", sum);
+  root.SetDouble("sum", static_cast<double>(sum));
   root.SetInteger("flags", flags());
   root.Set("params", parameters.release());
   root.Set("buckets", buckets.release());