SF: Move HWComposerBufferCache in to CompositionEngine

This simply moves DisplayHardware/HWComposerBufferCache.* to
CompositionEngine/HwcBufferCache.*, adjusting the existing code to
reference the moved file and namespace.

This is a prelude to moving the layerBE state into CompositionEngine.

Test: atest libsurfaceflinger_unittest libcompositionengine_test
Bug: 121291683
Change-Id: Id1e907963d0453ec7beea285ab384a963c356f89
diff --git a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
index 87ae7dd..d6543d1 100644
--- a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
+++ b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
@@ -21,11 +21,11 @@
 #include <string>
 
 #include <compositionengine/DisplaySurface.h>
+#include <compositionengine/impl/HwcBufferCache.h>
 #include <gui/ConsumerBase.h>
 #include <gui/IGraphicBufferProducer.h>
 
 #include "DisplayIdentification.h"
-#include "HWComposerBufferCache.h"
 
 // ---------------------------------------------------------------------------
 namespace android {
@@ -253,7 +253,7 @@
 
     bool mMustRecompose;
 
-    HWComposerBufferCache mHwcBufferCache;
+    compositionengine::impl::HwcBufferCache mHwcBufferCache;
 
     bool mForceHwcCopy;
 };