Refactor histogram_macros.h. This improves documentation for the macros in the file, moves LOCAL_* …

base/metrics/histogram_snapshot_manager.h

Index: base/metrics/histogram_snapshot_manager.h
diff --git a/base/metrics/histogram_snapshot_manager.h b/base/metrics/histogram_snapshot_manager.h
index 26fb93fd2022cc52a4990af14e61c6de57d65376..de4a2e195a1a725a789f0cd346ae84f023681881 100644
--- a/base/metrics/histogram_snapshot_manager.h
+++ b/base/metrics/histogram_snapshot_manager.h
@@ -24,7 +24,7 @@ class HistogramFlattener;
 // histograms for recording either to disk or for transmission (such as from
 // renderer to browser, or from browser to UMA upload). Since histograms can sit
 // in memory for an extended period of time, and are vulnerable to memory
-// corruption, this class also validates as much rendundancy as it can before
+// corruption, this class also validates as much redundancy as it can before
 // calling for the marginal change (a.k.a., delta) in a histogram to be
 // recorded.
 class BASE_EXPORT HistogramSnapshotManager {