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/BufferLayer.cpp b/services/surfaceflinger/BufferLayer.cpp
index 3dbc136..82f398e 100644
--- a/services/surfaceflinger/BufferLayer.cpp
+++ b/services/surfaceflinger/BufferLayer.cpp
@@ -683,9 +683,9 @@
     // Add this buffer from our internal queue tracker
     { // Autolock scope
         Mutex::Autolock lock(mQueueItemLock);
-        mFlinger->mInterceptor.saveBufferUpdate(this, item.mGraphicBuffer->getWidth(),
-                                                item.mGraphicBuffer->getHeight(),
-                                                item.mFrameNumber);
+        mFlinger->mInterceptor->saveBufferUpdate(this, item.mGraphicBuffer->getWidth(),
+                                                 item.mGraphicBuffer->getHeight(),
+                                                 item.mFrameNumber);
         // Reset the frame number tracker when we receive the first buffer after
         // a frame number reset
         if (item.mFrameNumber == 1) {