Cleanup histograms from message loop, as well as kHexRangePrintingFlag.

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 <limits.h>
 #include <stddef.h>
 #include <stdint.h>
@@ skipping 103 matching lines @@
     // histograms can be in performance critical code, and this allows us
     // to shortcut looking up the callback if it doesn't exist.
     kCallbackExists = 0x20,
 
     // Indicates that the histogram is held in "persistent" memory and may
     // be accessible between processes. This is only possible if such a
     // memory segment has been created/attached, used to create a Persistent-
     // MemoryAllocator, and that loaded into the Histogram module before this
     // histogram is created.
     kIsPersistent = 0x40,
-
-    // TODO(rkaplow): Look into this, but looks like this is unused and can
-    // be removed.
-    // Only for Histogram and its sub classes: fancy bucket-naming support.
-    kHexRangePrintingFlag = 0x8000,
   };
 
   // Histogram data inconsistency types.
   enum Inconsistency : uint32_t {
     NO_INCONSISTENCIES = 0x0,
     RANGE_CHECKSUM_ERROR = 0x1,
     BUCKET_ORDER_ERROR = 0x2,
     COUNT_HIGH_ERROR = 0x4,
     COUNT_LOW_ERROR = 0x8,
 
@@ skipping 133 matching lines @@
 
   const std::string histogram_name_;
   AtomicCount flags_;
 
   DISALLOW_COPY_AND_ASSIGN(HistogramBase);
 };
 
 }  // namespace base
 
 #endif  // BASE_METRICS_HISTOGRAM_BASE_H_