Change how the quota system computes the total poolsize for temporary storage

chrome/browser/extensions/extension_storage_monitor.cc

Index: chrome/browser/extensions/extension_storage_monitor.cc
diff --git a/chrome/browser/extensions/extension_storage_monitor.cc b/chrome/browser/extensions/extension_storage_monitor.cc
index 7294fbd4fc8a03d9da3bbb61cd4b0667e620df2b..81394f5609bafc272711c2f7fa52fbcef88191ab 100644
--- a/chrome/browser/extensions/extension_storage_monitor.cc
+++ b/chrome/browser/extensions/extension_storage_monitor.cc
@@ -84,17 +84,16 @@ const Extension* GetExtensionById(content::BrowserContext* context,
       extension_id, ExtensionRegistry::EVERYTHING);
 }
 
-void LogTemporaryStorageUsage(int64_t usage,
-                              storage::QuotaStatusCode status,
-                              int64_t global_quota) {
-  if (status == storage::kQuotaStatusOk) {
-    int64_t per_app_quota =
-        global_quota / storage::QuotaManager::kPerHostTemporaryPortion;
+void LogTemporaryStorageUsage(
+    scoped_refptr<storage::QuotaManager> quota_manager,
+    int64_t usage) {
+  const storage::QuotaSettings& settings = quota_manager->settings();
+  if (settings.per_host_quota > 0) {

[Devlin, 2016/11/23 17:04:13]

nit: since we only use per_host_quota here, maybe just cache that instead of the
full QuotaSettings?  (Possibly moot with below.)

     // Note we use COUNTS_100 (instead of PERCENT) because this can potentially
     // exceed 100%.
     UMA_HISTOGRAM_COUNTS_100(
         "Extensions.HostedAppUnlimitedStorageTemporaryStorageUsage",
-        100.0 * usage / per_app_quota);
+        100.0 * usage / settings.per_host_quota);
   }
 }
 
@@ -235,12 +234,9 @@ class StorageEventObserver
       } else {
         // We can't use the quota in the event because it assumes unlimited
         // storage.
-        BrowserThread::PostTask(
-            BrowserThread::IO,
-            FROM_HERE,
-            base::Bind(&storage::QuotaManager::GetTemporaryGlobalQuota,
-                       state.quota_manager,
-                       base::Bind(&LogTemporaryStorageUsage, event.usage)));
+        BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
+                                base::Bind(&LogTemporaryStorageUsage,
+                                           state.quota_manager, event.usage));

[Devlin, 2016/11/23 17:04:13]

Is per_host_quota able to change between when the state is created and now?  If
not, we could cache it on the StorageState and just pass that in, rather than
needing to pass the refcounted quota manager.  (If it is going to change, then
this is fine.)

[michaeln, 2016/12/06 00:35:54]

the setting values can change over time, i think the StorageState intances are
long lived, if so then we have to sample the settings value each time

       }
     }