drive: Rewrite UpdateOpreation to access cache/metadata on the blocking pool

chrome/browser/chromeos/drive/file_system/update_operation_unittest.cc

Index: chrome/browser/chromeos/drive/file_system/update_operation_unittest.cc
diff --git a/chrome/browser/chromeos/drive/file_system/update_operation_unittest.cc b/chrome/browser/chromeos/drive/file_system/update_operation_unittest.cc
index c09ce2037d79ec01a687139131d33145704655ec..5cb1b129bfd837ebacab8eed302b49826cb2f3d7 100644
--- a/chrome/browser/chromeos/drive/file_system/update_operation_unittest.cc
+++ b/chrome/browser/chromeos/drive/file_system/update_operation_unittest.cc
@@ -17,8 +17,11 @@ class UpdateOperationTest : public OperationTestBase {
  protected:
   virtual void SetUp() OVERRIDE {
    OperationTestBase::SetUp();
-   operation_.reset(
-       new UpdateOperation(observer(), scheduler(), metadata(), cache()));
+   operation_.reset(new UpdateOperation(blocking_task_runner(),
+                                        observer(),
+                                        scheduler(),
+                                        metadata(),
+                                        cache()));
  }
 
  virtual void TearDown() OVERRIDE {