Remove DisplayChangeObserver ash dependencies.

ui/display/manager/display_manager.cc

Index: ui/display/manager/display_manager.cc
diff --git a/ui/display/manager/display_manager.cc b/ui/display/manager/display_manager.cc
index 5279bc938fefede662530de2835961ad30bddc79..8573cd4f6d0799b24d7e3f183f7d57e072e71daf 100644
--- a/ui/display/manager/display_manager.cc
+++ b/ui/display/manager/display_manager.cc
@@ -129,8 +129,11 @@ using std::vector;
 // static
 int64_t DisplayManager::kUnifiedDisplayId = -10;
 
-DisplayManager::DisplayManager(std::unique_ptr<Screen> screen)
+DisplayManager::DisplayManager(
+    std::unique_ptr<Screen> screen,
+    std::unique_ptr<DisplayStringProvider> string_provider)
     : screen_(std::move(screen)),
+      string_provider_(std::move(string_provider)),
       layout_store_(new DisplayLayoutStore),
       weak_ptr_factory_(this) {
 #if defined(OS_CHROMEOS)
@@ -582,7 +585,7 @@ void DisplayManager::OnNativeDisplaysChanged(
       // in docked mode.
       ManagedDisplayInfo internal_display_info(
           Display::InternalDisplayId(),
-          delegate_->GetInternalDisplayNameString(),
+          string_provider_->GetInternalDisplayNameString(),
           false /*Internal display must not have overscan */);
       internal_display_info.SetBounds(gfx::Rect(0, 0, 800, 600));
       display_info_[Display::InternalDisplayId()] = internal_display_info;
@@ -900,7 +903,7 @@ const Display DisplayManager::GetMirroringDisplayById(
 
 std::string DisplayManager::GetDisplayNameForId(int64_t id) {
   if (id == kInvalidDisplayId)
-    return delegate_->GetInternalDisplayNameString();
+    return string_provider_->GetInternalDisplayNameString();
 
   std::map<int64_t, ManagedDisplayInfo>::const_iterator iter =
       display_info_.find(id);