Add display task to trigger display configuration

ui/display/chromeos/display_configurator.h

Index: ui/display/chromeos/display_configurator.h
diff --git a/ui/display/chromeos/display_configurator.h b/ui/display/chromeos/display_configurator.h
index f13d7821d63ed0056a85c7d80704a9c65ce3ee36..5abbccb08ee65314a3f5a0498c6b3bf11a36845a 100644
--- a/ui/display/chromeos/display_configurator.h
+++ b/ui/display/chromeos/display_configurator.h
@@ -16,6 +16,7 @@
 #include "base/observer_list.h"
 #include "base/timer/timer.h"
 #include "third_party/cros_system_api/dbus/service_constants.h"
+#include "ui/display/chromeos/configure_displays_task.h"
 #include "ui/display/display_export.h"
 #include "ui/display/types/display_constants.h"
 #include "ui/display/types/native_display_observer.h"
@@ -94,6 +95,40 @@ class DISPLAY_EXPORT DisplayConfigurator : public NativeDisplayObserver {
     virtual bool SoftwareMirroringEnabled() const = 0;
   };
 
+  class DisplayLayoutManager {
+   public:
+    virtual ~DisplayLayoutManager() {}
+
+    virtual SoftwareMirroringController* GetSoftwareMirroringController()
+        const = 0;
+
+    virtual StateController* GetStateController() const = 0;
+
+    // Returns the current display state.
+    virtual MultipleDisplayState GetDisplayState() const = 0;
+
+    // Returns the current power state.
+    virtual chromeos::DisplayPowerState GetPowerState() const = 0;
+
+    // Parses the displays and adds |mirror_mode| and |selected_mode|.

[Daniel Erat, 2014/12/11 23:34:07]

the mirror_mode and selected_mode mentions seem confusing; there aren't any
arguments or members with those names. are those fields within DisplayState? if
so, i'd probably say something like "... and sets mirrored and selected modes
within the return DisplayStates." instead

+    // TODO(dnicoara): This operation doesn't depend on state and could be done
+    // directly in |GetDisplayLayout()|. Though I need to make sure that there
+    // are no uses for those fields outside DisplayConfigurator.
+    virtual std::vector<DisplayState> ParseDisplays(
+        const std::vector<DisplaySnapshot*>& displays) const = 0;
+
+    // Based on the given |displays|, display state and power state, it will
+    // create display configuration requests which will then be used to
+    // configure the hardware. The requested configuration is stored in
+    // |requests| and |framebuffer_size|.
+    virtual bool GetDisplayLayout(
+        const std::vector<DisplayState>& displays,
+        MultipleDisplayState new_display_state,
+        chromeos::DisplayPowerState new_power_state,
+        std::vector<DisplayConfigureRequest>* requests,
+        gfx::Size* framebuffer_size) const = 0;
+  };
+
   // Helper class used by tests.
   class TestApi {
    public: