Pass actual present time to ViewRootImpl

To measure end-to-end touch latency, we need to report the actual
present time to ViewRootImpl. ViewRootImpl, in turn, will report this
information to InputDispatcher. Finally, InputDispatcher will combine
all known information for a specific input event, and will report this
data to westworld.

In another patch, we will add a new call, 'reportLatencyInfo', to
InputPublisher. This call will allow the app to send this latency data
to InputDispatcher.

Bug: 169866723
Test: printed the input event present times inside ViewRootImpl
Change-Id: Ibd3a2cfeb1a340eb15cd2165071df1f8589634af

1 files changed, 18 insertions, 0 deletions

diff --git a/libs/hwui/FrameMetricsObserver.h b/libs/hwui/FrameMetricsObserver.h
index b93f07853242..ef1f5aabcbd8 100644
--- a/libs/hwui/FrameMetricsObserver.h
+++ b/libs/hwui/FrameMetricsObserver.h
@@ -24,6 +24,24 @@ namespace uirenderer {
 class FrameMetricsObserver : public VirtualLightRefBase {
 public:
     virtual void notify(const int64_t* buffer) = 0;
+    bool waitForPresentTime() const { return mWaitForPresentTime; };
+
+    /**
+     * Create a new metrics observer. An observer that watches present time gets notified at a
+     * different time than the observer that doesn't.
+     *
+     * The observer that doesn't want present time is notified about metrics just after the frame
+     * is completed. This is the default behaviour that's used by public API's.
+     *
+     * An observer that watches present time is notified about metrics after the actual display
+     * present time is known.
+     * WARNING! This observer may not receive metrics for the last several frames that the app
+     * produces.
+     */
+    FrameMetricsObserver(bool waitForPresentTime) : mWaitForPresentTime(waitForPresentTime) {}
+
+private:
+    const bool mWaitForPresentTime;
 };
 
 }  // namespace uirenderer