Quota: Convert to constexpr.

Change-Id: I164a3e7233fe2e7d07fc6e5b05adc68b04022ee4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2285909
Auto-Submit: Jarryd Goodman <jarrydg@chromium.org>
Commit-Queue: Darwin Huang <huangdarwin@chromium.org>
Reviewed-by: Darwin Huang <huangdarwin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#786129}

storage/browser/quota/quota_temporary_storage_evictor.cc

@@ -22,11 +22,11 @@
       base::TimeDelta::FromDays(1), 50)
 
 namespace {
-const int64_t kMBytes = 1024 * 1024;
-const double kUsageRatioToStartEviction = 0.7;
-const int kThresholdOfErrorsToStopEviction = 5;
-const int kHistogramReportIntervalMinutes = 60;
-const double kDiskSpaceShortageAllowanceRatio = 0.5;
+constexpr int64_t kMBytes = 1024 * 1024;
+constexpr double kUsageRatioToStartEviction = 0.7;
+constexpr int kThresholdOfErrorsToStopEviction = 5;
+constexpr int kHistogramReportIntervalMinutes = 60;
+constexpr double kDiskSpaceShortageAllowanceRatio = 0.5;
 }
 
 namespace storage {