Add "panel_fitting" GPU feature type and use it for mirror mode.

chromeos/display/output_configurator.h

Index: chromeos/display/output_configurator.h
diff --git a/chromeos/display/output_configurator.h b/chromeos/display/output_configurator.h
index 4e2b10e37fe58a5e0324a6aeee2301a864d7119a..df5f6387592a4a79144c07356cd284d11b280351 100644
--- a/chromeos/display/output_configurator.h
+++ b/chromeos/display/output_configurator.h
@@ -21,11 +21,17 @@ typedef XID RROutput;
 typedef XID RRCrtc;
 typedef XID RRMode;
 
+struct _XDisplay;
+typedef struct _XDisplay Display;
+struct _XRROutputInfo;
+typedef _XRROutputInfo XRROutputInfo;
 struct _XRRScreenResources;
 typedef _XRRScreenResources XRRScreenResources;
 
 namespace chromeos {
 
+struct OutputSnapshot;
+
 // Used to describe the state of a multi-display configuration.
 // TODO(oshima): remove DUAL_SECONDARY_ONLY
 enum OutputState {
@@ -48,10 +54,10 @@ class CHROMEOS_EXPORT OutputConfigurator : public MessageLoop::Dispatcher {
    public:
     // Called when the change of the display mode finished.  It will usually
     // start the fading in the displays.
-    virtual void OnDisplayModeChanged() {};
+    virtual void OnDisplayModeChanged() {}
 
     // Called when the change of the display mode is issued but failed.
-    virtual void OnDisplayModeChangeFailed() {};
+    virtual void OnDisplayModeChangeFailed() {}
   };
 
   OutputConfigurator();
@@ -61,6 +67,10 @@ class CHROMEOS_EXPORT OutputConfigurator : public MessageLoop::Dispatcher {
 
   OutputState output_state() const { return output_state_; }
 
+  // Initialization, must be called right after constructor.
+  // |is_panel_fitting_enabled| indicates hardware panel fitting support.
+  void Init(bool is_panel_fitting_enabled);
+
   // Called when the user hits ctrl-F4 to request a display mode change.
   // This method should only return false if it was called in a single-head or
   // headless mode.
@@ -93,6 +103,37 @@ class CHROMEOS_EXPORT OutputConfigurator : public MessageLoop::Dispatcher {
   // Fires OnDisplayModeChanged() event to the observers.
   void NotifyOnDisplayChanged();
 
+  // Fills output parameters |one| and |two| with properties of
+  // first two connected outputs found on |display| and |screen|.
+  int GetDualOutputs(Display* display,
+                     XRRScreenResources* screen,
+                     OutputSnapshot* one,
+                     OutputSnapshot* two);
+
+  // Should be called if the internal (built-in) output didn't advertise a mode
+  // which would be capable to support mirror mode.
+  // Relies on hardware panel fitting support,
+  // returns immediately if it is not available.
+  // Tries to add the native mode of the external output to the internal output,
+  // assuming panel fitter hardware will take care of scaling and letterboxing.
+  // The RROutput IDs |output_one| and |output_two| are used
+  // to look up the modes and configure the internal output,
+  // |output_one_mode| and |output_two_mode| are the out-parameters
+  // for the modes on the two outputs which will have same resolution.
+  // Returns false if it fails to configure the internal output appropriately.
+  bool AddMirrorModeToInternalOutput(Display* display,
+                                     XRRScreenResources* screen,
+                                     RROutput output_one,
+                                     RROutput output_two,
+                                     RRMode* output_one_mode,
+                                     RRMode* output_two_mode);
+
+  // Tells if the output specified by |output_info| is for internal display.
+  static bool IsInternalOutput(const XRROutputInfo* output_info);
+
+  // Returns output's native mode, None if not found.
+  static RRMode GetOutputNativeMode(const XRROutputInfo* output_info);
+
   // This is detected by the constructor to determine whether or not we should
   // be enabled.  If we aren't running on ChromeOS, we can't assume that the
   // Xrandr X11 extension is supported.
@@ -100,6 +141,10 @@ class CHROMEOS_EXPORT OutputConfigurator : public MessageLoop::Dispatcher {
   // configuration to immediately fail without changing the state.
   bool is_running_on_chrome_os_;
 
+  // This is set externally in Init,
+  // and is used to enable modes which rely on panel fitting.
+  bool is_panel_fitting_enabled_;
+
   // The number of outputs that are connected.
   int connected_output_count_;