Create gfx::Screen at startup for cast_shell

chromecast/browser/cast_browser_main_parts.cc

Index: chromecast/browser/cast_browser_main_parts.cc
diff --git a/chromecast/browser/cast_browser_main_parts.cc b/chromecast/browser/cast_browser_main_parts.cc
index f1dfbe33e4f0fa87bdf4b5e849af9bada29fd72f..5f0bd93f01ca8fa52155d3c937ba791e29b440bf 100644
--- a/chromecast/browser/cast_browser_main_parts.cc
+++ b/chromecast/browser/cast_browser_main_parts.cc
@@ -40,6 +40,11 @@
 #include "net/android/network_change_notifier_factory_android.h"
 #endif
 
+#if defined(USE_AURA)
+#include "ui/aura/test/test_screen.h"
+#include "ui/gfx/screen.h"
+#endif
+
 namespace {
 
 #if !defined(OS_ANDROID)
@@ -194,6 +199,16 @@ int CastBrowserMainParts::PreCreateThreads() {
   if (!base::CreateDirectory(home_dir))
     return 1;
 #endif
+
+#if defined(USE_AURA)
+  // Screen can (and should) exist even with no displays connected. Its presence
+  // is assumed as an interface to access display information, e.g. from metrics
+  // code.  See CastContentWindow::CreateWindowTree for update when resolution
+  // is available.
+  DCHECK(!gfx::Screen::GetScreenByType(gfx::SCREEN_TYPE_NATIVE));
+  gfx::Screen::SetScreenInstance(gfx::SCREEN_TYPE_NATIVE,
+                                 aura::TestScreen::Create(gfx::Size(0, 0)));

[oshima, 2015/03/25 22:39:55]

Hmm, production code should not depend on test code, but looks like this is
already used in cast. lgtm for now, but could you please create cast's screen
and remove the dependency to test?

[halliwell, 2015/03/26 00:28:24]

Yes, sure.  I filed https://code.google.com/p/chromium/issues/detail?id=470735
to follow up on this.

And to clarify - should we just create our own Screen implementation?  We have a
TODO in CastContentWindow::CreateWindowTree that suggests "use ozone's screen
implementation when it is ready" ... does that still apply?

+#endif
   return 0;
 }