Add setting to isolate zoom changes by default.

chrome/browser/ui/zoom/chrome_zoom_level_prefs.cc

Index: chrome/browser/ui/zoom/chrome_zoom_level_prefs.cc
diff --git a/chrome/browser/ui/zoom/chrome_zoom_level_prefs.cc b/chrome/browser/ui/zoom/chrome_zoom_level_prefs.cc
index 65576ae8c34a1564339f73fcabfc979a81b829a7..6246ef7359acfd73ea845e1891356920a71d7259 100644
--- a/chrome/browser/ui/zoom/chrome_zoom_level_prefs.cc
+++ b/chrome/browser/ui/zoom/chrome_zoom_level_prefs.cc
@@ -7,48 +7,29 @@
 #include <stddef.h>
 
 #include "base/bind.h"
-#include "base/strings/string_number_conversions.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/values.h"
+#include "chrome/browser/ui/zoom/chrome_zoom_prefs_helper.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/pref_names.h"
-#include "components/prefs/json_pref_store.h"
-#include "components/prefs/pref_filter.h"
-#include "components/prefs/pref_registry_simple.h"
-#include "components/prefs/pref_service_factory.h"
 #include "components/prefs/scoped_user_pref_update.h"
 #include "components/zoom/zoom_event_manager.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/host_zoom_map.h"
 #include "content/public/common/page_zoom.h"
 
-namespace {
-
-std::string GetHash(const base::FilePath& relative_path) {
-  size_t int_key = BASE_HASH_NAMESPACE::hash<base::FilePath>()(relative_path);
-  return base::SizeTToString(int_key);
-}
-
-}  // namespace
-
 ChromeZoomLevelPrefs::ChromeZoomLevelPrefs(
     PrefService* pref_service,
     const base::FilePath& profile_path,
     const base::FilePath& partition_path,
     base::WeakPtr<zoom::ZoomEventManager> zoom_event_manager)
-    : pref_service_(pref_service),
+    : partitioned_prefs_(pref_service, profile_path, partition_path),
       zoom_event_manager_(zoom_event_manager),
       host_zoom_map_(nullptr) {
-  DCHECK(pref_service_);
-
-  DCHECK(!partition_path.empty());
-  DCHECK((partition_path == profile_path) ||
-         profile_path.IsParent(partition_path));
-  // Create a partition_key string with no '.'s in it. For the default
-  // StoragePartition, this string will always be "0".
-  base::FilePath partition_relative_path;
-  profile_path.AppendRelativePath(partition_path, &partition_relative_path);
-  partition_key_ = GetHash(partition_relative_path);
-
+  // If this is the default partition, emit the zoom scope setting.
+  if (profile_path == partition_path)
+    UMA_HISTOGRAM_BOOLEAN("Settings.ZoomScopeIsPerOrigin",
+                          GetZoomScopeIsPerOriginPref());
 }
 
 ChromeZoomLevelPrefs::~ChromeZoomLevelPrefs() {
@@ -56,15 +37,14 @@ ChromeZoomLevelPrefs::~ChromeZoomLevelPrefs() {
 
 std::string ChromeZoomLevelPrefs::GetHashForTesting(
     const base::FilePath& relative_path) {
-  return GetHash(relative_path);
+  return ChromeZoomPrefsHelper::GetHashForTesting(relative_path);
 }
 
 void ChromeZoomLevelPrefs::SetDefaultZoomLevelPref(double level) {
   if (content::ZoomValuesEqual(level, host_zoom_map_->GetDefaultZoomLevel()))
     return;
 
-  DictionaryPrefUpdate update(pref_service_, prefs::kPartitionDefaultZoomLevel);
-  update->SetDouble(partition_key_, level);
+  partitioned_prefs_.SetDouble(prefs::kPartitionDefaultZoomLevel, level);
   // For unregistered paths, OnDefaultZoomLevelChanged won't be called, so
   // set this manually.
   host_zoom_map_->SetDefaultZoomLevel(level);
@@ -76,11 +56,10 @@ void ChromeZoomLevelPrefs::SetDefaultZoomLevelPref(double level) {
 double ChromeZoomLevelPrefs::GetDefaultZoomLevelPref() const {
   double default_zoom_level = 0.0;
 
-  const base::DictionaryValue* default_zoom_level_dictionary =
-      pref_service_->GetDictionary(prefs::kPartitionDefaultZoomLevel);
   // If no default has been previously set, the default returned is the
   // value used to initialize default_zoom_level in this function.
-  default_zoom_level_dictionary->GetDouble(partition_key_, &default_zoom_level);
+  partitioned_prefs_.GetDouble(prefs::kPartitionDefaultZoomLevel,
+                               &default_zoom_level);
   return default_zoom_level;
 }
 
@@ -90,6 +69,31 @@ ChromeZoomLevelPrefs::RegisterDefaultZoomLevelCallback(
   return default_zoom_changed_callbacks_.Add(callback);
 }
 
+void ChromeZoomLevelPrefs::SetZoomScopeIsPerOriginPref(bool is_per_origin) {
+  if (is_per_origin == GetZoomScopeIsPerOriginPref())
+    return;
+
+  partitioned_prefs_.SetBoolean(prefs::kPartitionZoomScopeIsPerOrigin,
+                                is_per_origin);
+  default_scope_changed_callbacks_.Notify();
+}
+
+bool ChromeZoomLevelPrefs::GetZoomScopeIsPerOriginPref() const {
+  bool is_per_origin = kZoomScopeSettingDefault;
+
+  // If no value has been previously set, |is_per_origin| will be untouched
+  // from the default value we've set above.
+  partitioned_prefs_.GetBoolean(prefs::kPartitionZoomScopeIsPerOrigin,
+                                &is_per_origin);
+  return is_per_origin;
+}
+
+std::unique_ptr<ChromeZoomLevelPrefs::DefaultZoomScopeSubscription>
+ChromeZoomLevelPrefs::RegisterDefaultZoomScopeCallback(
+    const base::Closure& callback) {
+  return default_scope_changed_callbacks_.Add(callback);
+}
+
 void ChromeZoomLevelPrefs::OnZoomLevelChanged(
     const content::HostZoomMap::ZoomLevelChange& change) {
   // If there's a manager to aggregate ZoomLevelChanged events, pass this event
@@ -101,20 +105,14 @@ void ChromeZoomLevelPrefs::OnZoomLevelChanged(
   if (change.mode != content::HostZoomMap::ZOOM_CHANGED_FOR_HOST)
     return;
   double level = change.zoom_level;
-  DictionaryPrefUpdate update(pref_service_,
-                              prefs::kPartitionPerHostZoomLevels);
-  base::DictionaryValue* host_zoom_dictionaries = update.Get();
-  DCHECK(host_zoom_dictionaries);
+  std::unique_ptr<DictionaryPrefUpdate> update(
+      partitioned_prefs_.GetUpdate(prefs::kPartitionPerHostZoomLevels));
 
   bool modification_is_removal =
       content::ZoomValuesEqual(level, host_zoom_map_->GetDefaultZoomLevel());
 
-  base::DictionaryValue* host_zoom_dictionary = nullptr;
-  if (!host_zoom_dictionaries->GetDictionary(partition_key_,
-                                             &host_zoom_dictionary)) {
-    host_zoom_dictionary = new base::DictionaryValue();
-    host_zoom_dictionaries->Set(partition_key_, host_zoom_dictionary);
-  }
+  base::DictionaryValue* host_zoom_dictionary(
+      partitioned_prefs_.GetMutableDictionary(update.get()));
 
   if (modification_is_removal)
     host_zoom_dictionary->RemoveWithoutPathExpansion(change.host, nullptr);
@@ -166,12 +164,10 @@ void ChromeZoomLevelPrefs::ExtractPerHostZoomLevels(
   // Sanitize prefs to remove entries that match the default zoom level and/or
   // have an empty host.
   {
-    DictionaryPrefUpdate update(pref_service_,
-                                prefs::kPartitionPerHostZoomLevels);
-    base::DictionaryValue* host_zoom_dictionaries = update.Get();
-    base::DictionaryValue* host_zoom_dictionary = nullptr;
-    host_zoom_dictionaries->GetDictionary(partition_key_,
-                                          &host_zoom_dictionary);
+    std::unique_ptr<DictionaryPrefUpdate> update(
+        partitioned_prefs_.GetUpdate(prefs::kPartitionPerHostZoomLevels));
+    base::DictionaryValue* host_zoom_dictionary(
+        partitioned_prefs_.GetMutableDictionary(update.get()));
     for (const std::string& s : keys_to_remove)
       host_zoom_dictionary->RemoveWithoutPathExpansion(s, nullptr);
   }
@@ -189,11 +185,9 @@ void ChromeZoomLevelPrefs::InitHostZoomMap(
 
   // Initialize the HostZoomMap with per-host zoom levels from the persisted
   // zoom-level preference values.
-  const base::DictionaryValue* host_zoom_dictionaries =
-      pref_service_->GetDictionary(prefs::kPartitionPerHostZoomLevels);
   const base::DictionaryValue* host_zoom_dictionary = nullptr;
-  if (host_zoom_dictionaries->GetDictionary(partition_key_,
-                                            &host_zoom_dictionary)) {
+  if (partitioned_prefs_.GetDictionary(prefs::kPartitionPerHostZoomLevels,
+                                       &host_zoom_dictionary)) {
     // Since we're calling this before setting up zoom_subscription_ below we
     // don't need to worry that host_zoom_dictionary is indirectly affected
     // by calls to HostZoomMap::SetZoomLevelForHost().