hwc: Rename libexternal to serve HDMI as primary or external

This change will make is easier to build new functionality
applicable to both HDMI scenarios.

Change-Id: I417184568cb65a49c2ccb4199aff313ae2ee9b24
diff --git a/libhwcomposer/hwc_utils.h b/libhwcomposer/hwc_utils.h
index 041ca74..cae22f1 100644
--- a/libhwcomposer/hwc_utils.h
+++ b/libhwcomposer/hwc_utils.h
@@ -62,7 +62,7 @@
 namespace qhwc {
 //fwrd decl
 class QueuedBufferStore;
-class ExternalDisplay;
+class HDMIDisplay;
 class VirtualDisplay;
 class IFBUpdate;
 class IVideoOverlay;
@@ -545,8 +545,9 @@
 
     //Primary and external FB updater
     qhwc::IFBUpdate *mFBUpdate[HWC_NUM_DISPLAY_TYPES];
-    // External display related information
-    qhwc::ExternalDisplay *mExtDisplay;
+    // HDMI display related object. Used to configure/teardown
+    // HDMI when it is connected as primary or external.
+    qhwc::HDMIDisplay *mHDMIDisplay;
     qhwc::MDPInfo mMDP;
     qhwc::VsyncState vstate;
     qhwc::DisplayAttributes dpyAttr[HWC_NUM_DISPLAY_TYPES];