Remove implicit conversions from scoped_refptr to T* in PasswordStoreMac test.

- Add a .get() to a boolean test until boolean tests on scoped_refptr
  can be re-enabled.
- Change the test fixture store() accessor to just return a raw pointer,
  since no one depends on it returning a scoped_refptr anyway.

BUG=110610
TBR=stuartmorgan@chromium.org

Review URL: https://codereview.chromium.org/584373002

Cr-Commit-Position: refs/heads/master@{#295873}

chrome/browser/password_manager/password_store_mac_unittest.cc

@@ -1070,7 +1070,7 @@ class PasswordStoreMacTest : public testing::Test {
 
   virtual void TearDown() {
     store_->Shutdown();
-    EXPECT_FALSE(store_->GetBackgroundTaskRunner());
+    EXPECT_FALSE(store_->GetBackgroundTaskRunner().get());
   }
 
   void WaitForStoreUpdate() {
@@ -1082,7 +1082,7 @@ class PasswordStoreMacTest : public testing::Test {
     base::MessageLoop::current()->Run();
   }
 
-  scoped_refptr<TestPasswordStoreMac> store() { return store_; }
+  TestPasswordStoreMac* store() { return store_.get(); }
 
   MockAppleKeychain* keychain() { return keychain_; }