Add policy for ash launcher auto-hide behavior

chrome/browser/ui/ash/launcher/chrome_launcher_controller.cc

Index: chrome/browser/ui/ash/launcher/chrome_launcher_controller.cc
diff --git a/chrome/browser/ui/ash/launcher/chrome_launcher_controller.cc b/chrome/browser/ui/ash/launcher/chrome_launcher_controller.cc
index f48a8158ebfe134bc451c7dee7ebe0ab40f81169..66336782c5f435e85ce8c02f1ce3a6a7c86d09c7 100644
--- a/chrome/browser/ui/ash/launcher/chrome_launcher_controller.cc
+++ b/chrome/browser/ui/ash/launcher/chrome_launcher_controller.cc
@@ -126,12 +126,12 @@ std::string GetLocalOrRemotePref(PrefService* pref_service,
   return value.empty() ? pref_service->GetString(synced_path) : value;
 }
 
-// If prefs have synced and the pref value at |local_path| is empty the value
+// If prefs have synced and no user-set value exists at |local_path|, the value
 // from |synced_path| is copied to |local_path|.
 void MaybePropagatePrefToLocal(PrefService* pref_service,
                                const char* local_path,
                                const char* synced_path) {
-  if (pref_service->GetString(local_path).empty() &&
+  if (!pref_service->FindPreference(local_path)->HasUserSetting() &&

[sky, 2012/11/29 23:46:06]

I'm not familiar with HasUserSetting. How does this differ than the old code?

[bartfab (slow), 2012/11/30 11:55:47]

A quick bit of context: There are multiple sources of pref settings with
precedence increasing as: default, recommended, user, mandatory. Before policies
were added to the game here, the pref at |local_path| could either have a
default value (which is empty) or be user-set to some other value (which is
non-empty). So the current code worked as expected.

Now that policy can be used to control |local_path|, a non-empty pref value no
means that the user set a value. It could be coming from one of the other
sources, e.g. recommended or mandatory policy. The HasUserSetting() call does
what it says on the tin, it checks whether there actually is a user-set value or
not.

And a final bit of context: If there is no user-set value, line 138 will copy a
value from |synced_path| to |local_path|. If mandatory policy is in effect, it
will still continue to take precedence and the value just copied will be ignored
for now. But if policies goes away at any time (and it can, the admin can change
policy), the value will come into effect. So it is important to copy the value,
even if it should be currently overridden by policy.

       pref_service->IsSyncing()) {
     // First time the user is using this machine, propagate from remote to
     // local.
@@ -176,6 +176,8 @@ ChromeLauncherController::ChromeLauncherController(Profile* profile,
                               content::Source<Profile>(profile_));
   pref_change_registrar_.Init(profile_->GetPrefs());
   pref_change_registrar_.Add(prefs::kPinnedLauncherApps, this);
+  pref_change_registrar_.Add(prefs::kShelfAlignmentLocal, this);
+  pref_change_registrar_.Add(prefs::kShelfAutoHideBehaviorLocal, this);
 }
 
 ChromeLauncherController::~ChromeLauncherController() {
@@ -557,28 +559,39 @@ bool ChromeLauncherController::CanPin() const {
   return pref && pref->IsUserModifiable();
 }
 
-void ChromeLauncherController::SetAutoHideBehavior(
-    ash::ShelfAutoHideBehavior behavior,
-    aura::RootWindow* root_window) {
-  ash::Shell::GetInstance()->SetShelfAutoHideBehavior(
-      behavior,
-      root_window);
-  // TODO(oshima): Support multiple launcher.
-  if (root_window != ash::Shell::GetPrimaryRootWindow())
-    return;
+ash::ShelfAutoHideBehavior ChromeLauncherController::GetShelfAutoHideBehavior(
+    aura::RootWindow* root_window) const {
+  // TODO(oshima): Support multiple launchers.
 
-  const char* value = NULL;
-  switch (behavior) {
-    case ash::SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS:
-      value = ash::kShelfAutoHideBehaviorAlways;
-      break;
-    case ash::SHELF_AUTO_HIDE_BEHAVIOR_NEVER:
-      value = ash::kShelfAutoHideBehaviorNever;
-      break;
-  }
-  // See comment in |kShelfAlignment| about why we have two prefs here.
-  profile_->GetPrefs()->SetString(prefs::kShelfAutoHideBehaviorLocal, value);
-  profile_->GetPrefs()->SetString(prefs::kShelfAutoHideBehavior, value);
+  // See comment in |kShelfAlignment| as to why we consider two prefs.
+  const std::string behavior_value(
+      GetLocalOrRemotePref(profile_->GetPrefs(),
+                           prefs::kShelfAutoHideBehaviorLocal,
+                           prefs::kShelfAutoHideBehavior));
+
+  // Note: To maintain sync compatibility with old images of chrome/chromeos
+  // the set of values that may be encountered includes the now-extinct
+  // "Default" as well as "Never" and "Always", "Default" should now
+  // be treated as "Never" (http://crbug.com/146773).
+  if (behavior_value == ash::kShelfAutoHideBehaviorAlways)
+    return ash::SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS;
+  return ash::SHELF_AUTO_HIDE_BEHAVIOR_NEVER;
+}
+
+bool ChromeLauncherController::CanUserModifyShelfAutoHideBehavior(
+    aura::RootWindow* root_window) const {
+  // TODO(oshima): Support multiple launchers.
+  return profile_->GetPrefs()->
+      FindPreference(prefs::kShelfAutoHideBehaviorLocal)->IsUserModifiable();
+}
+
+void ChromeLauncherController::ToggleShelfAutoHideBehavior(
+    aura::RootWindow* root_window) {
+  ash::ShelfAutoHideBehavior behavior = GetShelfAutoHideBehavior(root_window) ==
+      ash::SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS ?
+          ash::SHELF_AUTO_HIDE_BEHAVIOR_NEVER :
+          ash::SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS;
+  SetShelfAutoHideBehaviorPrefs(behavior, root_window);
 }
 
 void ChromeLauncherController::RemoveTabFromRunningApp(
@@ -979,25 +992,32 @@ void ChromeLauncherController::UpdateAppLaunchersFromPref() {
     DoPinAppWithID(*pref_app_id);
 }
 
-void ChromeLauncherController::SetShelfAutoHideBehaviorFromPrefs() {
-  // See comment in |kShelfAlignment| as to why we consider two prefs.
-  const std::string behavior_value(
-      GetLocalOrRemotePref(profile_->GetPrefs(),
-                           prefs::kShelfAutoHideBehaviorLocal,
-                           prefs::kShelfAutoHideBehavior));
+void ChromeLauncherController::SetShelfAutoHideBehaviorPrefs(
+    ash::ShelfAutoHideBehavior behavior,
+    aura::RootWindow* root_window) {
+  // TODO(oshima): Support multiple launchers.
+  if (root_window != ash::Shell::GetPrimaryRootWindow())
+    return;
 
-  // Note: To maintain sync compatibility with old images of chrome/chromeos
-  // the set of values that may be encountered includes the now-extinct
-  // "Default" as well as "Never" and "Always", "Default" should now
-  // be treated as "Never".
-  // (http://code.google.com/p/chromium/issues/detail?id=146773)
-  ash::ShelfAutoHideBehavior behavior =
-      ash::SHELF_AUTO_HIDE_BEHAVIOR_NEVER;
-  if (behavior_value == ash::kShelfAutoHideBehaviorAlways)
-    behavior = ash::SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS;
+  const char* value = NULL;
+  switch (behavior) {
+    case ash::SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS:
+      value = ash::kShelfAutoHideBehaviorAlways;
+      break;
+    case ash::SHELF_AUTO_HIDE_BEHAVIOR_NEVER:
+      value = ash::kShelfAutoHideBehaviorNever;
+      break;
+  }
+  // See comment in |kShelfAlignment| about why we have two prefs here.
+  profile_->GetPrefs()->SetString(prefs::kShelfAutoHideBehaviorLocal, value);
+  profile_->GetPrefs()->SetString(prefs::kShelfAutoHideBehavior, value);
+}
+
+void ChromeLauncherController::SetShelfAutoHideBehaviorFromPrefs() {
   // TODO(oshima): Support multiple displays.
+  aura::RootWindow* root_window = ash::Shell::GetPrimaryRootWindow();
   ash::Shell::GetInstance()->SetShelfAutoHideBehavior(
-      behavior, ash::Shell::GetPrimaryRootWindow());
+      GetShelfAutoHideBehavior(root_window), root_window);
 }
 
 void ChromeLauncherController::SetShelfAlignmentFromPrefs() {