Update //base to chromium 9659b08ea5a34f889dc4166217f438095ddc10d2

base/metrics/histogram_base.h

 // 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.
 
 #ifndef BASE_METRICS_HISTOGRAM_BASE_H_
 #define BASE_METRICS_HISTOGRAM_BASE_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 13 matching lines @@
 class HistogramSamples;
 class ListValue;
 class Pickle;
 class PickleIterator;
 
 ////////////////////////////////////////////////////////////////////////////////
 // These enums are used to facilitate deserialization of histograms from other
 // processes into the browser. If you create another class that inherits from
 // HistogramBase, add new histogram types and names below.
 
-enum BASE_EXPORT HistogramType {
+enum HistogramType {
   HISTOGRAM,
   LINEAR_HISTOGRAM,
   BOOLEAN_HISTOGRAM,
   CUSTOM_HISTOGRAM,
   SPARSE_HISTOGRAM,
 };
 
 std::string HistogramTypeToString(HistogramType type);
 
 // Create or find existing histogram that matches the pickled info.
@@ skipping 22 matching lines @@
     // refer to |MetricsService::PrepareInitialStabilityLog|.
     kUmaStabilityHistogramFlag = kUmaTargetedHistogramFlag | 0x2,
 
     // Indicates that the histogram was pickled to be sent across an IPC
     // Channel. If we observe this flag on a histogram being aggregated into
     // after IPC, then we are running in a single process mode, and the
     // aggregation should not take place (as we would be aggregating back into
     // the source histogram!).
     kIPCSerializationSourceFlag = 0x10,
 
+    // Indicates that a callback exists for when a new sample is recorded on
+    // this histogram. We store this as a flag with the histogram since
+    // histograms can be in performance critical code, and this allows us
+    // to shortcut looking up the callback if it doesn't exist.
+    kCallbackExists = 0x20,
+
     // Only for Histogram and its sub classes: fancy bucket-naming support.
     kHexRangePrintingFlag = 0x8000,
   };
 
   // Histogram data inconsistency types.
   enum Inconsistency {
     NO_INCONSISTENCIES = 0x0,
     RANGE_CHECKSUM_ERROR = 0x1,
     BUCKET_ORDER_ERROR = 0x2,
     COUNT_HIGH_ERROR = 0x4,
     COUNT_LOW_ERROR = 0x8,
 
     NEVER_EXCEEDED_VALUE = 0x10
   };
 
   explicit HistogramBase(const std::string& name);
   virtual ~HistogramBase();
 
-  std::string histogram_name() const { return histogram_name_; }
+  const std::string& histogram_name() const { return histogram_name_; }
 
   // Comapres |name| to the histogram name and triggers a DCHECK if they do not
   // match. This is a helper function used by histogram macros, which results in
   // in more compact machine code being generated by the macros.
   void CheckName(const StringPiece& name) const;
 
   // Operations with Flags enum.
   int32_t flags() const { return flags_; }
   void SetFlags(int32_t flags);
   void ClearFlags(int32_t flags);
@@ skipping 59 matching lines @@
 
   // Return a string description of what goes in a given bucket.
   const std::string GetSimpleAsciiBucketRange(Sample sample) const;
 
   // Write textual description of the bucket contents (relative to histogram).
   // Output is the count in the buckets, as well as the percentage.
   void WriteAsciiBucketValue(Count current,
                              double scaled_sum,
                              std::string* output) const;
 
+  // Retrieves the callback for this histogram, if one exists, and runs it
+  // passing |sample| as the parameter.
+  void FindAndRunCallback(Sample sample) const;
+
  private:
   const std::string histogram_name_;
   int32_t flags_;
 
   DISALLOW_COPY_AND_ASSIGN(HistogramBase);
 };
 
 }  // namespace base
 
 #endif  // BASE_METRICS_HISTOGRAM_BASE_H_