Variable time resolution in histogram (Jiffy)

Changed variable types to make them more consistent,
e.g., always use int64_t. Made histogram take up less
space by adjusting the column with for each value.
Example of results (only the fastmixer histogram's
left half is shown, not the slowmixer's).

Occurrences
  2    2    2    7   21   44  122  416  394  123

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                 |    |    |    |    |    |    |
  |    |    |    |    |    |    |    |    |    |
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 ________________________________________________
3.2  3.3  3.4  3.5  3.6  3.7  3.8  3.9  4.0     ms

Test: dumpsys media.log

Change-Id: I007a6104c3f62ab04ee386a1de196b267adddecc
diff --git a/media/libnbaio/ReportPerformance.cpp b/media/libnbaio/ReportPerformance.cpp
index fa2b9a0..813df94 100644
--- a/media/libnbaio/ReportPerformance.cpp
+++ b/media/libnbaio/ReportPerformance.cpp
@@ -39,7 +39,7 @@
 // Writes outlier intervals, timestamps, and histograms spanning long time intervals to a file.
 // TODO: format the data efficiently and write different types of data to different files
 void writeToFile(const std::deque<std::pair<timestamp, Histogram>> &hists,
-                 const std::deque<std::pair<outlierInterval, timestamp>> &outlierData,
+                 const std::deque<std::pair<msInterval, timestamp>> &outlierData,
                  const std::deque<timestamp> &peakTimestamps,
                  const char * directory, bool append, int author, log_hash_t hash) {
     if (outlierData.empty() || hists.empty()) {
@@ -65,9 +65,10 @@
     for (const auto &hist : hists) {
         hfs << "\ttimestamp\n";
         hfs << hist.first << "\n";
-        hfs << "\tbuckets and counts\n";
+        hfs << "\tbuckets (in ms) and counts\n";
         for (const auto &bucket : hist.second) {
-            hfs << bucket.first << ": " << bucket.second << "\n";
+            hfs << bucket.first / static_cast<double>(kJiffyPerMs)
+                    << ": " << bucket.second << "\n";
         }
         hfs << "\n"; // separate histograms with a newline
     }