SF: Separate SurfaceInterceptor into interface and impl

SurfaceInterceptor is now an abstract interface.
impl::SurfaceInterceptor is the normal implementation.

This allows unit tests to replace it with a GMock.

Test: Builds
Bug: 74827900
Change-Id: I4d5bb2649b0c7a8ec1e6c0abf01ab53174d06a19
diff --git a/services/surfaceflinger/SurfaceInterceptor.cpp b/services/surfaceflinger/SurfaceInterceptor.cpp
index eeb4929..4596a21 100644
--- a/services/surfaceflinger/SurfaceInterceptor.cpp
+++ b/services/surfaceflinger/SurfaceInterceptor.cpp
@@ -31,6 +31,10 @@
 
 // ----------------------------------------------------------------------------
 
+SurfaceInterceptor::~SurfaceInterceptor() = default;
+
+namespace impl {
+
 SurfaceInterceptor::SurfaceInterceptor(SurfaceFlinger* flinger)
     :   mFlinger(flinger)
 {
@@ -593,5 +597,5 @@
     addPowerModeUpdateLocked(createTraceIncrementLocked(), displayId, mode);
 }
 
-
+} // namespace impl
 } // namespace android