SF: libsurfaceflinger_unittest should skip SF ctor

This reduces the cost of constructing a SurfaceFlinger instance for each
test, but it means the tests must take care to set up all internal state
that is needed for each test.

[Test execution time reduced from 6.1 to 3.1ms]

Test: libsurfaceflinger_unittest passes on Pixel XL
Bug: 74827900
Change-Id: I7eed4fd274cae521fe0f22b655cf3343cee66342

3 files changed, 8 insertions, 3 deletions

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index cb410a14e1..db472a7396 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -162,7 +162,7 @@ SurfaceFlingerBE::SurfaceFlingerBE()
         mComposerSequenceId(0) {
 }
 
-SurfaceFlinger::SurfaceFlinger()
+SurfaceFlinger::SurfaceFlinger(SurfaceFlinger::SkipInitializationTag)
       : BnSurfaceComposer(),
         mTransactionFlags(0),
         mTransactionPending(false),
@@ -194,7 +194,9 @@ SurfaceFlinger::SurfaceFlinger()
         mNumLayers(0),
         mVrFlingerRequestsDisplay(false),
         mMainThreadId(std::this_thread::get_id()),
-        mCreateBufferQueue(&BufferQueue::createBufferQueue) {
+        mCreateBufferQueue(&BufferQueue::createBufferQueue) {}
+
+SurfaceFlinger::SurfaceFlinger() : SurfaceFlinger(SkipInitialization) {
     ALOGI("SurfaceFlinger is starting");
 
     vsyncPhaseOffsetNs = getInt64< ISurfaceFlingerConfigs,
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 392acaa0a6..db541fe747 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -265,6 +265,9 @@ public:
         return "SurfaceFlinger";
     }
 
+    struct SkipInitializationTag {};
+    static constexpr SkipInitializationTag SkipInitialization;
+    explicit SurfaceFlinger(SkipInitializationTag) ANDROID_API;
     SurfaceFlinger() ANDROID_API;
 
     // must be called before clients can connect
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index 067b09ad02..3e58eb8813 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -98,7 +98,7 @@ public:
         auto& mutableConfigs() { return this->mConfigs; }
     };
 
-    sp<SurfaceFlinger> mFlinger = new SurfaceFlinger();
+    sp<SurfaceFlinger> mFlinger = new SurfaceFlinger(SurfaceFlinger::SkipInitialization);
 };
 
 } // namespace android