Add UMA private PPAPI interface for UMA logging from NaCl plugin

webkit/plugins/ppapi/ppb_uma_private_impl.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 "webkit/plugins/ppapi/ppb_uma_private_impl.h"
+
+#include "base/metrics/histogram.h"
+#include "ppapi/c/pp_var.h"
+#include "ppapi/c/private/ppb_uma_private.h"
+#include "webkit/glue/webkit_glue.h"
+#include "webkit/plugins/ppapi/var.h"
+
+namespace webkit {
+namespace ppapi {
+
+namespace {
+
+void HistogramCustomTimes(PP_Var name,
+                          int64_t sample,
+                          int64_t min, int64_t max,
+                          uint32_t bucket_count) {
+  scoped_refptr<StringVar> name_string(StringVar::FromPPVar(name));

[brettw, 2011/04/29 21:05:05]

You should NULL check these values (same below) in case somebody sends an
invalid string.

[elijahtaylor (use chromium), 2011/04/29 21:52:08]

I noticed other badness that could happen with invalid args, so I created a
macro (don't hit me) to check for errors in the args and return (fail silently).
 I assume this is preferred to CHECK failures in ppb interfaces.

+  base::Histogram* counter =
+    base::Histogram::FactoryTimeGet(name_string->value(),
+                                    base::TimeDelta::FromMilliseconds(min),
+                                    base::TimeDelta::FromMilliseconds(max),
+                                    bucket_count,
+                                    base::Histogram::kUmaTargetedHistogramFlag);
+  counter->AddTime(base::TimeDelta::FromMilliseconds(sample));
+}
+
+void HistogramCustomCounts(PP_Var name,
+                           int32_t sample,
+                           int32_t min, int32_t max,
+                           uint32_t bucket_count) {
+  scoped_refptr<StringVar> name_string(StringVar::FromPPVar(name));
+  base::Histogram* counter =
+    base::Histogram::FactoryGet(name_string->value(),min, max, bucket_count,
+                                base::Histogram::kUmaTargetedHistogramFlag);
+  counter->Add(sample);
+}
+
+void HistogramEnumeration(PP_Var name,
+                          int32_t sample,
+                          int32_t boundary_value) {
+  scoped_refptr<StringVar> name_string(StringVar::FromPPVar(name));
+  base::Histogram* counter =
+    base::LinearHistogram::FactoryGet(name_string->value(), 1, boundary_value,

[brettw, 2011/04/29 21:05:05]

This should use 4-space indents (same above).

[elijahtaylor (use chromium), 2011/04/29 21:52:08]

Done.

+      boundary_value + 1, base::Histogram::kUmaTargetedHistogramFlag);
+  counter->Add(sample);
+}
+
+}  // namespace
+
+const PPB_UMA_Private ppb_uma = {
+  &HistogramCustomTimes,
+  &HistogramCustomCounts,
+  &HistogramEnumeration,
+};
+
+// static
+const PPB_UMA_Private* PPB_UMA_Private_Impl::GetInterface() {
+  return &ppb_uma;
+}
+
+}  // namespace ppapi
+}  // namespace webkit