Only enumerate display_timing when present timestamp supported

Test: CTS and cube demo.
Bug: 36887025

Vulkan should only enumerate the VK_GOOGLE_display_timing extension if
the device supports reliably returning the present timestamp.  Vulkan
will determine this by reading a property that SurfaceFlinger will set
(based on the HWC2::Capability::PresentFenceIsNotReliable capability).

Change-Id: I6025be5f9120a8f02f228b8437b64be4ff8cfb17
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index d72b3b5..61ceda4 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -578,6 +578,14 @@
 
     Mutex::Autolock _l(mStateLock);
 
+    // Inform native graphics APIs whether the present timestamp is supported:
+    if (getHwComposer().hasCapability(
+            HWC2::Capability::PresentFenceIsNotReliable)) {
+        property_set(kTimestampProperty, "0");
+    } else {
+        property_set(kTimestampProperty, "1");
+    }
+
     if (useVrFlinger) {
         auto vrFlingerRequestDisplayCallback = [this] (bool requestDisplay) {
             mVrFlingerRequestsDisplay = requestDisplay;
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index e15c6ff..e9c0acf 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -228,6 +228,7 @@
     enum { LOG_FRAME_STATS_PERIOD =  30*60*60 };
 
     static const size_t MAX_LAYERS = 4096;
+    static constexpr const char* kTimestampProperty = "service.sf.present_timestamp";
 
     // We're reference counted, never destroy SurfaceFlinger directly
     virtual ~SurfaceFlinger();
diff --git a/services/surfaceflinger/SurfaceFlinger_hwc1.cpp b/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
index a9000c0..bdaf85d 100644
--- a/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
+++ b/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
@@ -549,6 +549,9 @@
     LOG_ALWAYS_FATAL_IF(mEGLContext == EGL_NO_CONTEXT,
             "couldn't create EGLContext");
 
+    // Inform native graphics APIs that the present timestamp is NOT supported:
+    property_set(kTimestampProperty, "0");
+
     // initialize our non-virtual displays
     for (size_t i=0 ; i<DisplayDevice::NUM_BUILTIN_DISPLAY_TYPES ; i++) {
         DisplayDevice::DisplayType type((DisplayDevice::DisplayType)i);
diff --git a/vulkan/libvulkan/driver.cpp b/vulkan/libvulkan/driver.cpp
index 212d142..f2cd8e6 100644
--- a/vulkan/libvulkan/driver.cpp
+++ b/vulkan/libvulkan/driver.cpp
@@ -817,9 +817,6 @@
     loader_extensions.push_back({
         VK_KHR_INCREMENTAL_PRESENT_EXTENSION_NAME,
         VK_KHR_INCREMENTAL_PRESENT_SPEC_VERSION});
-    loader_extensions.push_back({
-        VK_GOOGLE_DISPLAY_TIMING_EXTENSION_NAME,
-        VK_GOOGLE_DISPLAY_TIMING_SPEC_VERSION});
 
     if (kEnableUnratifiedExtensions) {
         // conditionally add shared_presentable_image if supportable
@@ -832,6 +829,16 @@
         }
     }
 
+    // conditionally add VK_GOOGLE_display_timing if present timestamps are
+    // supported by the driver:
+    char timestamp_property[PROPERTY_VALUE_MAX];
+    property_get("service.sf.present_timestamp", timestamp_property, "1");
+    if (strcmp(timestamp_property, "1") == 0) {
+        loader_extensions.push_back({
+                VK_GOOGLE_DISPLAY_TIMING_EXTENSION_NAME,
+                VK_GOOGLE_DISPLAY_TIMING_SPEC_VERSION});
+    }
+
     // enumerate our extensions first
     if (!pLayerName && pProperties) {
         uint32_t count = std::min(