Don't bother asking the platform for the delegates if they are already set

ui/display/chromeos/display_configurator.cc

 // Copyright 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 "ui/display/chromeos/display_configurator.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 161 matching lines @@
     chromeos::DisplayPowerState power_state) {
   DCHECK_EQ(display_state_, MULTIPLE_DISPLAY_STATE_INVALID);
   power_state_ = power_state;
 }
 
 void DisplayConfigurator::Init(bool is_panel_fitting_enabled) {
   is_panel_fitting_enabled_ = is_panel_fitting_enabled;
   if (!configure_display_)
     return;
 
-  PlatformInitialize();
+  // If the delegates are already initialized don't update them (For example,
+  // tests set their own delegates).
+  if (!native_display_delegate_ && !touchscreen_delegate_)
+    PlatformInitialize();

[Daniel Erat, 2014/07/09 18:11:24]

i'm concerned that someone further down the line will make PlatformInitialize()
do additional non-delegate initialization that'll then get skipped when the
delegates have been set earlier. could you refactor things to make this less
likely to happen by e.g. calling PlatformInitialize() unconditionally but
passing a |create_delegates| argument to it?

[dnicoara, 2014/07/09 19:24:36]

Hmm, I don't really want to add too much complexity around PlatformInitialize()
since it's really only used to create the platform delegates. What's your
opinion on dropping the PlatformInitialize() function and adding
CreatePlatformNativeDisplayDelegate() and CreatePlatformTouchscreenDelegate()?

 }
 
 void DisplayConfigurator::InitializeDelegates(
     scoped_ptr<NativeDisplayDelegate> display_delegate,
     scoped_ptr<TouchscreenDelegate> touchscreen_delegate) {
-  if (!native_display_delegate_ && !touchscreen_delegate_) {
-    native_display_delegate_ = display_delegate.Pass();
-    touchscreen_delegate_ = touchscreen_delegate.Pass();
+  native_display_delegate_ = display_delegate.Pass();
+  touchscreen_delegate_ = touchscreen_delegate.Pass();
 
-    native_display_delegate_->AddObserver(this);
-  }
+  native_display_delegate_->AddObserver(this);
 }
 
 void DisplayConfigurator::ForceInitialConfigure(
     uint32_t background_color_argb) {
   if (!configure_display_)
     return;
 
   native_display_delegate_->GrabServer();
   native_display_delegate_->Initialize();
 
@@ skipping 729 matching lines @@
         return state_controller_->GetStateForDisplayIds(display_ids);
       }
     }
     default:
       NOTREACHED();
   }
   return MULTIPLE_DISPLAY_STATE_INVALID;
 }
 
 }  // namespace ui