diff --git a/include/gui/FrameTimestamps.h b/include/gui/FrameTimestamps.h
index 8a3fa39..7d62706 100644
--- a/include/gui/FrameTimestamps.h
+++ b/include/gui/FrameTimestamps.h
@@ -116,13 +116,22 @@
 public:
     ~ProducerFrameEventHistory() override;
 
-    void updateAcquireFence(
+    // virtual for testing.
+    virtual void updateAcquireFence(
             uint64_t frameNumber, std::shared_ptr<FenceTime>&& acquire);
     void applyDelta(const FrameEventHistoryDelta& delta);
 
     void updateSignalTimes();
 
-private:
+protected:
+    void applyFenceDelta(FenceTimeline* timeline,
+            std::shared_ptr<FenceTime>* dst,
+            const FenceTime::Snapshot& src) const;
+
+    // virtual for testing.
+    virtual std::shared_ptr<FenceTime> createFenceTime(
+            const sp<Fence>& fence) const;
+
     size_t mAcquireOffset{0};
 
     // The consumer updates it's timelines in Layer and SurfaceFlinger since
diff --git a/include/gui/Surface.h b/include/gui/Surface.h
index 451bd68..43b8d96 100644
--- a/include/gui/Surface.h
+++ b/include/gui/Surface.h
@@ -33,6 +33,8 @@
 
 namespace android {
 
+class ISurfaceComposer;
+
 /*
  * An implementation of ANativeWindow that feeds graphics buffers into a
  * BufferQueue.
@@ -66,7 +68,8 @@
      * the controlledByApp flag indicates that this Surface (producer) is
      * controlled by the application. This flag is used at connect time.
      */
-    explicit Surface(const sp<IGraphicBufferProducer>& bufferProducer, bool controlledByApp = false);
+    explicit Surface(const sp<IGraphicBufferProducer>& bufferProducer,
+            bool controlledByApp = false);
 
     /* getIGraphicBufferProducer() returns the IGraphicBufferProducer this
      * Surface was created with. Usually it's an error to use the
@@ -152,6 +155,9 @@
 protected:
     virtual ~Surface();
 
+    // Virtual for testing.
+    virtual sp<ISurfaceComposer> composerService() const;
+
 private:
     // can't be copied
     Surface& operator = (const Surface& rhs);
@@ -245,7 +251,6 @@
     enum { NUM_BUFFER_SLOTS = BufferQueue::NUM_BUFFER_SLOTS };
     enum { DEFAULT_FORMAT = PIXEL_FORMAT_RGBA_8888 };
 
-private:
     void querySupportedTimestampsLocked() const;
 
     void freeAllBuffers();
@@ -399,7 +404,7 @@
 
     // A cached copy of the FrameEventHistory maintained by the consumer.
     bool mEnableFrameTimestamps = false;
-    ProducerFrameEventHistory mFrameEventHistory;
+    std::unique_ptr<ProducerFrameEventHistory> mFrameEventHistory;
 };
 
 namespace view {