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

chrome/browser/extensions/api/sync_file_system/sync_file_system_browsertest.cc

Index: chrome/browser/extensions/api/sync_file_system/sync_file_system_browsertest.cc
diff --git a/chrome/browser/extensions/api/sync_file_system/sync_file_system_browsertest.cc b/chrome/browser/extensions/api/sync_file_system/sync_file_system_browsertest.cc
index 0e13258bf3fcaacdd686b86d031e101640620093..549b4aaa415adf1b2f05ca09ed837e849575bf3d 100644
--- a/chrome/browser/extensions/api/sync_file_system/sync_file_system_browsertest.cc
+++ b/chrome/browser/extensions/api/sync_file_system/sync_file_system_browsertest.cc
@@ -18,7 +18,6 @@
 #include "chrome/browser/sync_file_system/sync_file_system_service.h"
 #include "chrome/browser/sync_file_system/sync_file_system_service_factory.h"
 #include "components/drive/service/fake_drive_service.h"
-#include "content/public/browser/storage_partition.h"
 #include "extensions/test/extension_test_message_listener.h"
 #include "extensions/test/result_catcher.h"
 #include "storage/browser/quota/quota_manager.h"
@@ -62,6 +61,19 @@ class SyncFileSystemTest : public extensions::PlatformAppBrowserTest,
       : remote_service_(NULL) {
   }
 
+  void SetUpInProcessBrowserTestFixture() override {
+    ExtensionApiTest::SetUpInProcessBrowserTestFixture();
+    real_minimum_preserved_space_ =
+        storage::QuotaManager::kMinimumPreserveForSystem;
+    storage::QuotaManager::kMinimumPreserveForSystem = 0;
+  }
+
+  void TearDownInProcessBrowserTestFixture() override {
+    storage::QuotaManager::kMinimumPreserveForSystem =
+        real_minimum_preserved_space_;
+    ExtensionApiTest::TearDownInProcessBrowserTestFixture();
+  }
+
   scoped_refptr<base::SequencedTaskRunner> MakeSequencedTaskRunner() {
     scoped_refptr<base::SequencedWorkerPool> worker_pool =
         content::BrowserThread::GetBlockingPool();
@@ -145,6 +157,8 @@ class SyncFileSystemTest : public extensions::PlatformAppBrowserTest,
 
   drive_backend::SyncEngine* remote_service_;
 
+  int64_t real_minimum_preserved_space_;
+
   DISALLOW_COPY_AND_ASSIGN(SyncFileSystemTest);
 };