Generalize support for per-display shelf prefs.

chrome/browser/ui/ash/chrome_launcher_prefs.cc

Index: chrome/browser/ui/ash/chrome_launcher_prefs.cc
diff --git a/chrome/browser/ui/ash/chrome_launcher_prefs.cc b/chrome/browser/ui/ash/chrome_launcher_prefs.cc
index b437cd32af6eac8421c6805aa6d51d1223b42ece..2b8084fbeac5bc243ec491d74829b6f0839b44dc 100644
--- a/chrome/browser/ui/ash/chrome_launcher_prefs.cc
+++ b/chrome/browser/ui/ash/chrome_launcher_prefs.cc
@@ -9,10 +9,18 @@
 #include <memory>
 
 #include "base/macros.h"
+#include "base/strings/string_number_conversions.h"
 #include "base/values.h"
+#include "chrome/browser/app_mode/app_mode_utils.h"
+#include "chrome/browser/profiles/profile.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/pref_names.h"
 #include "components/pref_registry/pref_registry_syncable.h"
+#include "components/prefs/pref_service.h"
+#include "components/prefs/scoped_user_pref_update.h"
+#include "ui/gfx/screen.h"
+
+namespace ash {
 
 namespace {
 
@@ -26,14 +34,140 @@ const char* kDefaultPinnedApps[] = {
 base::ListValue* CreateDefaultPinnedAppsList() {
   std::unique_ptr<base::ListValue> apps(new base::ListValue);
   for (size_t i = 0; i < arraysize(kDefaultPinnedApps); ++i)
-    apps->Append(ash::CreateAppDict(kDefaultPinnedApps[i]));
+    apps->Append(CreateAppDict(kDefaultPinnedApps[i]));
 
   return apps.release();
 }
 
-}  // namespace
+// Returns |profile|'s pref value for the display with the given |display_id|.
+// The pref value is stored in |local_path| and |path|, but the pref service may
+// have per-display preferences and the value can be specified by policy.
+// Here is the priority:
+//  * A value managed by policy. This is a single value that applies to all
+//    displays.
+//  * A user-set value for the specified display.
+//  * A user-set value in |local_path| or |path|, if no per-display settings are
+//    ever specified (see http://crbug.com/173719 for why). |local_path| is
+//    preferred. See comment in |kShelfAlignment| as to why we consider two
+//    prefs and why |local_path| is preferred.
+//  * A value recommended by policy. This is a single value that applies to all
+//    root windows.
+//  * The default value for |local_path| if the value is not recommended by
+//    policy.
+std::string GetPerDisplayPref(Profile* profile,
+                              int64_t display_id,
+                              const char* local_path,
+                              const char* path) {
+  PrefService* pref_service = profile->GetPrefs();
+  const PrefService::Preference* local_pref =
+      pref_service->FindPreference(local_path);
+  const std::string value(pref_service->GetString(local_path));
+  if (local_pref->IsManaged())
+    return value;
 
-namespace ash {
+  std::string pref_key = base::Int64ToString(display_id);
+  bool has_per_display_prefs = false;
+  if (!pref_key.empty()) {
+    const base::DictionaryValue* shelf_prefs =
+        pref_service->GetDictionary(prefs::kShelfPreferences);
+    const base::DictionaryValue* display_pref = nullptr;
+    std::string per_display_value;
+    if (shelf_prefs->GetDictionary(pref_key, &display_pref) &&
+        display_pref->GetString(path, &per_display_value))
+      return per_display_value;
+
+    // If the pref for the specified display is not found, scan the whole prefs
+    // and check if the prefs for other display is already specified.
+    std::string unused_value;
+    for (base::DictionaryValue::Iterator iter(*shelf_prefs); !iter.IsAtEnd();
+         iter.Advance()) {
+      const base::DictionaryValue* display_pref = nullptr;
+      if (iter.value().GetAsDictionary(&display_pref) &&
+          display_pref->GetString(path, &unused_value)) {
+        has_per_display_prefs = true;
+        break;
+      }
+    }
+  }
+
+  if (local_pref->IsRecommended() || !has_per_display_prefs)
+    return value;
+
+  const base::Value* default_value =
+      pref_service->GetDefaultPrefValue(local_path);
+  std::string default_string;
+  default_value->GetAsString(&default_string);
+  return default_string;
+}
+
+// Sets |profile|'s pref value for the display with the given |display_id|.
+void SetPerDisplayPref(Profile* profile,
+                       int64_t display_id,
+                       const char* pref_key,
+                       const std::string& value) {
+  if (display_id < 0)
+    return;
+
+  DictionaryPrefUpdate update(profile->GetPrefs(), prefs::kShelfPreferences);
+  base::DictionaryValue* shelf_prefs = update.Get();
+  base::DictionaryValue* prefs = nullptr;
+  std::string key = base::Int64ToString(display_id);
+  if (!shelf_prefs->GetDictionary(key, &prefs)) {
+    prefs = new base::DictionaryValue();
+    shelf_prefs->Set(key, prefs);
+  }
+  prefs->SetStringWithoutPathExpansion(pref_key, value);
+}
+
+ShelfAlignment AlignmentFromPref(const std::string& value) {
+  if (value == kShelfAlignmentLeft)
+    return SHELF_ALIGNMENT_LEFT;
+  else if (value == kShelfAlignmentRight)
+    return SHELF_ALIGNMENT_RIGHT;
+  // Default to bottom.
+  return SHELF_ALIGNMENT_BOTTOM;
+}
+
+const char* AlignmentToPref(ShelfAlignment alignment) {
+  switch (alignment) {
+    case SHELF_ALIGNMENT_BOTTOM:
+      return kShelfAlignmentBottom;
+    case SHELF_ALIGNMENT_LEFT:
+      return kShelfAlignmentLeft;
+    case SHELF_ALIGNMENT_RIGHT:
+      return kShelfAlignmentRight;
+  }
+  NOTREACHED();
+  return nullptr;
+}
+
+ShelfAutoHideBehavior AutoHideBehaviorFromPref(const std::string& value) {
+  // 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 (value == kShelfAutoHideBehaviorAlways)
+    return SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS;
+  return SHELF_AUTO_HIDE_BEHAVIOR_NEVER;
+}
+
+const char* AutoHideBehaviorToPref(ShelfAutoHideBehavior behavior) {
+  switch (behavior) {
+    case SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS:
+      return kShelfAutoHideBehaviorAlways;
+    case SHELF_AUTO_HIDE_BEHAVIOR_NEVER:
+      return kShelfAutoHideBehaviorNever;
+    case SHELF_AUTO_HIDE_ALWAYS_HIDDEN:
+      // This one should not be a valid preference option for now. We only want
+      // to completely hide it when we run in app mode - or while we temporarily
+      // hide the shelf as part of an animation (e.g. the multi user change).
+      return nullptr;
+  }
+  NOTREACHED();
+  return nullptr;
+}
+
+}  // namespace
 
 const char kPinnedAppsPrefAppIDPath[] = "id";
 const char kPinnedAppsPrefPinnedByPolicy[] = "pinned_by_policy";
@@ -77,52 +211,62 @@ base::DictionaryValue* CreateAppDict(const std::string& app_id) {
   return app_value.release();
 }
 
-ash::ShelfAlignment AlignmentFromPref(const std::string& value) {
-  if (value == ash::kShelfAlignmentLeft)
-    return ash::SHELF_ALIGNMENT_LEFT;
-  else if (value == ash::kShelfAlignmentRight)
-    return ash::SHELF_ALIGNMENT_RIGHT;
-  // Default to bottom.
-  return ash::SHELF_ALIGNMENT_BOTTOM;
+ShelfAutoHideBehavior GetShelfAutoHideBehaviorPref(Profile* profile,
+                                                   int64_t display_id) {
+  DCHECK(profile);
+  DCHECK_GE(display_id, 0);
+
+  // Don't show the shelf in app mode.
+  if (chrome::IsRunningInAppMode())
+    return SHELF_AUTO_HIDE_ALWAYS_HIDDEN;
+
+  // See comment in |kShelfAlignment| as to why we consider two prefs.
+  return AutoHideBehaviorFromPref(
+      GetPerDisplayPref(profile, display_id, prefs::kShelfAutoHideBehaviorLocal,
+                        prefs::kShelfAutoHideBehavior));
 }
 
-const char* AlignmentToPref(ash::ShelfAlignment alignment) {
-  switch (alignment) {
-    case ash::SHELF_ALIGNMENT_BOTTOM:
-      return ash::kShelfAlignmentBottom;
-    case ash::SHELF_ALIGNMENT_LEFT:
-      return ash::kShelfAlignmentLeft;
-    case ash::SHELF_ALIGNMENT_RIGHT:
-      return ash::kShelfAlignmentRight;
+void SetShelfAutoHideBehaviorPref(Profile* profile,
+                                  int64_t display_id,
+                                  ShelfAutoHideBehavior behavior) {
+  DCHECK(profile);
+  DCHECK_GE(display_id, 0);
+
+  const char* value = AutoHideBehaviorToPref(behavior);
+  if (!value)
+    return;
+
+  SetPerDisplayPref(profile, display_id, prefs::kShelfAutoHideBehavior, value);
+  if (display_id == gfx::Screen::GetScreen()->GetPrimaryDisplay().id()) {
+    // See comment in |kShelfAlignment| about why we have two prefs here.
+    profile->GetPrefs()->SetString(prefs::kShelfAutoHideBehaviorLocal, value);
+    profile->GetPrefs()->SetString(prefs::kShelfAutoHideBehavior, value);
   }
-  NOTREACHED();
-  return nullptr;
 }
 
-ash::ShelfAutoHideBehavior AutoHideBehaviorFromPref(const std::string& value) {
-  // 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 (value == ash::kShelfAutoHideBehaviorAlways)
-    return ash::SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS;
-  return ash::SHELF_AUTO_HIDE_BEHAVIOR_NEVER;
+ShelfAlignment GetShelfAlignmentPref(Profile* profile, int64_t display_id) {
+  DCHECK(profile);
+  DCHECK_GE(display_id, 0);
+
+  // See comment in |kShelfAlignment| as to why we consider two prefs.
+  return AlignmentFromPref(GetPerDisplayPref(profile, display_id,
+                                             prefs::kShelfAlignmentLocal,
+                                             prefs::kShelfAlignment));
 }
 
-const char* AutoHideBehaviorToPref(ash::ShelfAutoHideBehavior behavior) {
-  switch (behavior) {
-    case ash::SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS:
-      return ash::kShelfAutoHideBehaviorAlways;
-    case ash::SHELF_AUTO_HIDE_BEHAVIOR_NEVER:
-      return ash::kShelfAutoHideBehaviorNever;
-    case ash::SHELF_AUTO_HIDE_ALWAYS_HIDDEN:
-      // This one should not be a valid preference option for now. We only want
-      // to completely hide it when we run in app mode - or while we temporarily
-      // hide the shelf as part of an animation (e.g. the multi user change).
-      return nullptr;
+void SetShelfAlignmentPref(Profile* profile,
+                           int64_t display_id,
+                           ShelfAlignment alignment) {
+  DCHECK(profile);
+  DCHECK_GE(display_id, 0);
+
+  const char* value = AlignmentToPref(alignment);
+  SetPerDisplayPref(profile, display_id, prefs::kShelfAlignment, value);
+  if (display_id == gfx::Screen::GetScreen()->GetPrimaryDisplay().id()) {
+    // See comment in |kShelfAlignment| as to why we consider two prefs.
+    profile->GetPrefs()->SetString(prefs::kShelfAlignmentLocal, value);
+    profile->GetPrefs()->SetString(prefs::kShelfAlignment, value);
   }
-  NOTREACHED();
-  return nullptr;
 }
 
 }  // namespace ash