Create a PrefStore in support of Blimp metrics collection.

blimp/engine/common/blimp_pref_store.h

-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Copyright (c) 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.
 
-#ifndef ANDROID_WEBVIEW_BROWSER_AW_PREF_STORE_H_
-#define ANDROID_WEBVIEW_BROWSER_AW_PREF_STORE_H_
+#ifndef BLIMP_ENGINE_COMMON_BLIMP_PREF_STORE_H_
+#define BLIMP_ENGINE_COMMON_BLIMP_PREF_STORE_H_
 
 #include <stdint.h>
 
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "components/prefs/persistent_pref_store.h"
 #include "components/prefs/pref_value_map.h"
 
+namespace blimp {
+namespace engine {
 // A light-weight prefstore implementation that keeps preferences

[Kevin M, 2016/04/14 21:49:50]

Add newline above

[Jess, 2016/04/14 22:59:49]

Done.

 // in a memory backed store. This is not a persistent prefstore -- we
 // subclass the PersistentPrefStore here since it is needed by the
-// PrefService, which in turn is needed by the Autofill component.
-class AwPrefStore : public PersistentPrefStore {
+// PrefService, which in turn is needed by the metrics component.

[Kevin M, 2016/04/14 21:49:50]

Could you reference AwPrefStore as the basis for this class?

Have you considered making this a common class, e.g. InMemoryPrefStore, which
android_webview and Blimp can share?

[Jess, 2016/04/14 22:59:49]

Yes.

I'd been assuming the engine need something more in terms of PrefStore
relatively soon, which is why I copied instead of refactoring.

If that isn't the case, I'm happy to refactor things out. I'd appreciate some
guidance on Chromium best practices for this.  I'm not sure where the code would
live or how best to bring in the android webview folks onboard for the refactor.

+class BlimpPrefStore : public PersistentPrefStore {

[Kevin M, 2016/04/14 21:49:50]

Unit tests?

[Jess, 2016/04/14 22:59:49]

Do you have a specific function or set of function in mind? The parent classes
are doing the heavy lifting.

[Kevin M, 2016/04/15 17:45:38]

Can you inject a test-owned prefs_ and verify that the setters and getters are
passing through the data correctly, and invoking the observers when they should?

  public:
-  AwPrefStore();
+  BlimpPrefStore();
 
   // Overriden from PrefStore.

[Kevin M, 2016/04/14 21:49:50]

PrefStore implementation.

[Jess, 2016/04/14 22:59:49]

Done.

   bool GetValue(const std::string& key,
                 const base::Value** result) const override;
   void AddObserver(PrefStore::Observer* observer) override;
   void RemoveObserver(PrefStore::Observer* observer) override;
   bool HasObservers() const override;
   bool IsInitializationComplete() const override;
 
   // PersistentPrefStore overrides:

[Kevin M, 2016/04/14 21:49:50]

"PersistentPrefStore implementation."

[Jess, 2016/04/14 22:59:49]

Done.

   bool GetMutableValue(const std::string& key, base::Value** result) override;
   void ReportValueChanged(const std::string& key, uint32_t flags) override;
   void SetValue(const std::string& key,
                 std::unique_ptr<base::Value> value,
                 uint32_t flags) override;
   void SetValueSilently(const std::string& key,
                         std::unique_ptr<base::Value> value,
                         uint32_t flags) override;
   void RemoveValue(const std::string& key, uint32_t flags) override;
   bool ReadOnly() const override;
   PrefReadError GetReadError() const override;
   PersistentPrefStore::PrefReadError ReadPrefs() override;
   void ReadPrefsAsync(ReadErrorDelegate* error_delegate) override;
   void CommitPendingWrite() override {}
   void SchedulePendingLossyWrites() override {}
   void ClearMutableValues() override {}
 
  protected:
-  ~AwPrefStore() override;
+  ~BlimpPrefStore() override;
 
  private:
   // Stores the preference values.
   PrefValueMap prefs_;
 
   base::ObserverList<PrefStore::Observer, true> observers_;
 
-  DISALLOW_COPY_AND_ASSIGN(AwPrefStore);
+  DISALLOW_COPY_AND_ASSIGN(BlimpPrefStore);
 };
 
-#endif  // ANDROID_WEBVIEW_BROWSER_AW_PREF_STORE_H_
+}  // namespace engine
+}  // namespace blimp
+
+#endif  // BLIMP_ENGINE_COMMON_BLIMP_PREF_STORE_H_