Use stricter type checking in UMA_HISTOGRAM_ENUMERATION

ios/chrome/browser/ui/contextual_search/contextual_search_metrics.mm

 // Copyright 2014 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 "ios/chrome/browser/ui/contextual_search/contextual_search_metrics.h"
 
 #include <map>
 
 #include "base/metrics/histogram_macros.h"
 #include "base/time/time.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 using ContextualSearch::PanelState;
 using ContextualSearch::StateChangeReason;
 
 // TODO(crbug.com/546238): Convert this into a class that is injected into
 // CSController so it can be mocked and tested.
 
 #define VLOG_UMA_HISTOGRAM_ENUMERATION(log_level, name, sample) \
   DVLOG(log_level) << (name) << ": " << (sample);
 
 #define VLOG_UMA_HISTOGRAM_TIMES(log_level, name, sample) \
   DVLOG(log_level) << (name) << ": " << (sample).InMilliseconds();
 
 #define LOGGED_UMA_HISTOGRAM_ENUMERATION(name, sample, boundary, log_level) \
   {                                                                         \
-    int evaluated_sample = sample;                                          \
+    auto evaluated_sample = static_cast<decltype(boundary)>(sample);        \
     VLOG_UMA_HISTOGRAM_ENUMERATION(log_level, name, evaluated_sample);      \
     UMA_HISTOGRAM_ENUMERATION(name, evaluated_sample, boundary);            \
   }
 
 #define LOGGED_UMA_HISTOGRAM_TIMES(name, sample, log_level) \
   VLOG_UMA_HISTOGRAM_TIMES(log_level, name, sample);        \
   UMA_HISTOGRAM_TIMES(name, sample);
 
 namespace {
 // Constants used to log UMA "enum" histograms about the Contextual Search's
@@ skipping 744 matching lines @@
                              EXIT_MAXIMIZED_TO_OTHER),
           EXIT_MAXIMIZED_TO_COUNT, 1);
       break;
     default:
       NOTREACHED() << "RecordFirstStateExit for unexpected state " << to_state;
       break;
   }
 }
 
 }  // namespace ContextualSearch