fakehwc, libvr_hwc-hal: ComposerClient is moved

ComposerClient is moved to another library with some changes.  This
allows us to kill the has-a relation between VrComposerClient and
ComposerClientImpl in VR.

Test: builds
Change-Id: I0c32386f7d62f33e2e4d1271be42953f6880fd75
diff --git a/services/surfaceflinger/tests/fakehwc/FakeComposerClient.h b/services/surfaceflinger/tests/fakehwc/FakeComposerClient.h
index 7c111dc..95c274a 100644
--- a/services/surfaceflinger/tests/fakehwc/FakeComposerClient.h
+++ b/services/surfaceflinger/tests/fakehwc/FakeComposerClient.h
@@ -18,7 +18,7 @@
 
 #define HWC2_USE_CPP11
 #define HWC2_INCLUDE_STRINGIFICATION
-#include "ComposerClient.h"
+#include <composer-hal/2.1/ComposerClient.h>
 #undef HWC2_USE_CPP11
 #undef HWC2_INCLUDE_STRINGIFICATION
 #include "RenderState.h"
@@ -32,7 +32,6 @@
 
 using namespace android::hardware::graphics::composer::V2_1;
 using namespace android::hardware::graphics::composer::V2_1::hal;
-using namespace android::hardware::graphics::composer::V2_1::implementation;
 using namespace android::hardware;
 using namespace std::chrono_literals;