Lazily create PPDCache directory on first store.

chromeos/printing/ppd_cache_unittest.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/hash.h"
@@ skipping 34 matching lines @@
 
 // This fixture just points the cache at a temporary directory for the life of
 // the test.
 class PpdCacheTest : public ::testing::Test {
  public:
   void SetUp() override {
     ASSERT_TRUE(ppd_cache_temp_dir_.CreateUniqueTempDir());
   }
 
   // Make and return a cache for the test that uses a temporary directory
-  // which is cleaned up at the end of the test.
+  // which is cleaned up at the end of the test.  Note that we pass
+  // a (nonexistant) subdirectory of temp_dir_ to the cache to exercise
+  // the lazy-creation-of-the-cache-directory code.
   std::unique_ptr<PpdCache> CreateTestCache(
       const PpdCache::Options& options = PpdCache::Options()) {
-    return PpdCache::Create(ppd_cache_temp_dir_.GetPath(), options);
+    return PpdCache::Create(ppd_cache_temp_dir_.GetPath().Append("Cache"),
+                            options);
   }
 
  protected:
   // Overrider for DIR_CHROMEOS_PPD_CACHE that points it at a temporary
   // directory for the life of the test.
   base::ScopedTempDir ppd_cache_temp_dir_;
 };
 
 // Check that path has a value, and the contents of the referenced file are
 // |expected_contents|.
@@ skipping 115 matching lines @@
   cache->StoreAvailablePrinters(
       base::MakeUnique<PpdProvider::AvailablePrintersMap>());
 
   // Should *miss* in the cache because the entry is already expired.
   EXPECT_EQ(nullptr, cache->FindAvailablePrinters());
 }
 
 }  // namespace
 }  // namespace printing
 }  // namespace chromeos