Add ObjC API for getting native histograms.

webrtc/sdk/objc/Framework/Classes/RTCMetricsSampleInfo.mm

+/*
+ *  Copyright 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#import "RTCMetricsSampleInfo+Private.h"
+
+#import "NSString+StdString.h"
+
+@implementation RTCMetricsSampleInfo
+
+@synthesize name = _name;
+@synthesize min = _min;
+@synthesize max = _max;
+@synthesize bucketCount = _bucketCount;
+@synthesize samples = _samples;
+
+#pragma mark - Private
+
+- (instancetype)initWithNativeSampleInfo:
+    (const webrtc::metrics::SampleInfo&)info {
+  if (self = [super init]) {
+    _name = [NSString stringForStdString:info.name];
+    _min = info.min;
+    _max = info.max;
+    _bucketCount = info.bucket_count;
+
+    NSMutableDictionary* samples =
+        [NSMutableDictionary dictionaryWithCapacity:info.samples.size()];
+    for (auto const& sample : info.samples) {
+      NSNumber* key = [NSNumber numberWithInt:sample.first];
+      NSNumber* value = [NSNumber numberWithInt:sample.second];
+      [samples setObject:value forKey:key];

[tkchin_webrtc, 2016/06/06 17:32:51]

hm, I guess we haven't updated our mac deployment target.

use [samples setObject:@(sample.second) forKey:@(sample.first)] then

[åsapersson, 2016/06/07 06:10:25]

Done.

+    }
+    _samples = samples;
+  }
+  return self;
+}
+
+@end