Introduce ChromeZoomLevelPref, make zoom level prefs independent of profile prefs.

chrome/browser/ui/zoom/zoom_level_prefs_store_impl.cc

+// Copyright (c) 2014 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 "chrome/browser/ui/zoom/zoom_level_prefs_store_impl.h"
+
+#include "base/bind.h"
+#include "base/files/file_path.h"
+#include "base/prefs/json_pref_store.h"
+#include "base/prefs/pref_filter.h"
+#include "base/prefs/scoped_user_pref_update.h"
+#include "base/values.h"
+#include "chrome/browser/prefs/pref_service_syncable.h"
+#include "chrome/browser/prefs/pref_service_syncable_factory.h"
+#include "chrome/common/chrome_constants.h"
+#include "chrome/common/pref_names.h"
+#include "components/pref_registry/pref_registry_syncable.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/host_zoom_map.h"
+#include "content/public/common/page_zoom.h"
+
+namespace chrome {
+
+ZoomLevelPrefsStoreImpl::ZoomLevelPrefsStoreImpl()
+    : host_zoom_map_(NULL) {}
+
+void ZoomLevelPrefsStoreImpl::SetInitCallback(const base::Closure& callback) {

[sky, 2014/09/05 19:28:07]

Make order match header.

[wjmaclean, 2014/09/05 21:01:47]

Done.

+  callback_ = callback;
+}
+
+void ZoomLevelPrefsStoreImpl::InitPrefsAndCopyToHostZoomMap(
+    const base::FilePath& file_path,
+    content::HostZoomMap* host_zoom_map) {
+  DCHECK(!file_path.empty());
+  DCHECK(host_zoom_map);
+  host_zoom_map_ = host_zoom_map;
+
+  base::FilePath file_name(
+      file_path.Append(chrome::kZoomLevelPreferencesFilename));
+  zoom_level_prefs_ = new JsonPrefStore(
+      file_name,
+      JsonPrefStore::GetTaskRunnerForFile(
+          file_name, content::BrowserThread::GetBlockingPool()),
+      scoped_ptr<PrefFilter>());
+  scoped_refptr<user_prefs::PrefRegistrySyncable> registry =
+      new user_prefs::PrefRegistrySyncable();
+  registry->RegisterDoublePref(
+      prefs::kDefaultZoomLevel,
+      0.0,

[sky, 2014/09/05 19:28:07]

Why is the default 0 and not 1?

[wjmaclean, 2014/09/05 21:01:47]

Zoom levels are logarithmic, so level = 0 => zoom factor = 1, factors > 1 have
levels > 0, and factors < 1 have levels < 0.

+      user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+  registry->RegisterDictionaryPref(
+      prefs::kPerHostZoomLevels,
+      user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+
+  PrefServiceSyncableFactory factory;
+  factory.set_user_prefs(zoom_level_prefs_);
+  factory.set_async(true);
+
+  zoom_level_prefs_->AddObserver(this);
+
+  pref_service_ = factory.CreateSyncable(registry.get());
+}
+
+PrefService* ZoomLevelPrefsStoreImpl::GetPrefs() {
+  return pref_service_.get();
+}
+
+void ZoomLevelPrefsStoreImpl::OnPrefValueChanged(const std::string& key) {
+  // Push changes to the default zoom level to the HostZoomMap; all
+  // other consumers will get it from there.
+  if (key == prefs::kDefaultZoomLevel)

[sky, 2014/09/05 19:28:07]

nit: I would use {} as it's multiple lines.

[wjmaclean, 2014/09/05 21:01:47]

Done. Thanks for catching that!

+    host_zoom_map_->SetDefaultZoomLevel(
+        pref_service_->GetDouble(prefs::kDefaultZoomLevel));
+}
+
+void ZoomLevelPrefsStoreImpl::OnInitializationCompleted(bool succeeded) {
+  if (!succeeded) {

[sky, 2014/09/05 19:28:07]

nit: no {}

[wjmaclean, 2014/09/05 21:01:47]

Done. Ditto!

+    return;
+  }
+  double default_zoom_level =

[sky, 2014/09/05 19:28:07]

Add a comment as to what this does.

[wjmaclean, 2014/09/05 21:01:47]

Done.

+      pref_service_->GetDouble(prefs::kDefaultZoomLevel);
+  host_zoom_map_->SetDefaultZoomLevel(default_zoom_level);
+  const base::DictionaryValue* host_zoom_dictionary =
+            pref_service_->GetDictionary(prefs::kPerHostZoomLevels);
+  if (host_zoom_dictionary != NULL) {
+    std::vector<std::string> keys_to_remove;
+    for (base::DictionaryValue::Iterator i(*host_zoom_dictionary);
+         !i.IsAtEnd();
+         i.Advance()) {
+      const std::string& host(i.key());
+      double zoom_level = 0;
+
+      bool success = i.value().GetAsDouble(&zoom_level);
+      DCHECK(success);
+
+      if (host.empty() ||
+          content::ZoomValuesEqual(
+              zoom_level, host_zoom_map_->GetDefaultZoomLevel())) {
+        keys_to_remove.push_back(host);
+        continue;
+      }
+
+      host_zoom_map_->SetZoomLevelForHost(host, zoom_level);
+    }
+
+    // Sanitize prefs to remove entries that match the default zoom level and/or
+    // have an empty host.
+    DictionaryPrefUpdate update(pref_service_.get(), prefs::kPerHostZoomLevels);
+    base::DictionaryValue* host_zoom_dictionary = update.Get();
+    for (std::vector<std::string>::const_iterator it = keys_to_remove.begin();
+         it != keys_to_remove.end(); ++it) {
+      host_zoom_dictionary->RemoveWithoutPathExpansion(*it, NULL);
+    }
+  }
+  zoom_subscription_ = host_zoom_map_->AddZoomLevelChangedCallback(
+      base::Bind(&ZoomLevelPrefsStoreImpl::OnZoomLevelChanged,
+                 base::Unretained(this)));
+
+  if (!callback_.is_null()) {
+    callback_.Run();
+    // We'll never need to call this again.
+    callback_.Reset();
+  }
+}
+
+void ZoomLevelPrefsStoreImpl::OnZoomLevelChanged(
+    const content::HostZoomMap::ZoomLevelChange& change) {
+  if (change.mode != content::HostZoomMap::ZOOM_CHANGED_FOR_HOST)
+    return;
+  double level = change.zoom_level;
+  DictionaryPrefUpdate update(pref_service_.get(), prefs::kPerHostZoomLevels);
+  base::DictionaryValue* host_zoom_dictionary = update.Get();
+  if (content::ZoomValuesEqual(level, host_zoom_map_->GetDefaultZoomLevel()))
+    host_zoom_dictionary->RemoveWithoutPathExpansion(change.host, NULL);
+  else
+    host_zoom_dictionary->SetDoubleWithoutPathExpansion(change.host, level);
+}
+
+ZoomLevelPrefsStoreImpl::~ZoomLevelPrefsStoreImpl() {
+  zoom_subscription_.reset();
+  if (zoom_level_prefs_.get())

[sky, 2014/09/05 19:28:07]

Why the conditional here?

[wjmaclean, 2014/09/05 21:01:47]

Done. Looking at this again, this is leftover from an older version of the CL,
and is unecessary.

+    zoom_level_prefs_->RemoveObserver(this);
+}
+
+}  // namespace chrome