Quota: Make sure divisor is not 0 before dividing.

Bug: 956281
Change-Id: I8c9d37334c79b237e672aa0e8014b534d49f7898
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1585394
Commit-Queue: Jarryd Goodman <jarrydg@chromium.org>
Commit-Queue: Marijn Kruisselbrink <mek@chromium.org>
Auto-Submit: Jarryd Goodman <jarrydg@chromium.org>
Reviewed-by: Marijn Kruisselbrink <mek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654512}

storage/browser/quota/quota_manager.cc

@@ -1488,8 +1488,10 @@ void QuotaManager::DidGetStorageCapacityForHistogram(int64_t usage,
                                                      int64_t available_space) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   UMA_HISTOGRAM_MBYTES("Quota.GlobalUsageOfTemporaryStorage", usage);
-  UMA_HISTOGRAM_PERCENTAGE("Quota.PercentUsedForTemporaryStorage2",
-                           static_cast<int>((usage * 100) / total_space));
+  if (total_space > 0) {
+    UMA_HISTOGRAM_PERCENTAGE("Quota.PercentUsedForTemporaryStorage2",
+                             static_cast<int>((usage * 100) / total_space));
+  }
 
   GetGlobalUsage(
       StorageType::kPersistent,