Introduces GetStatusChangeTime

This provides a best-effort interface to retrieve the time at which
a GLFence changed state. This is useful for getting a render time
estimate without having to poll the fence or actively waiting for it
to signal.

Bug: none
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I4df20684fdaeb0f39b36fb72bd1d65a2766952fd
Reviewed-on: https://chromium-review.googlesource.com/1030049Reviewed-by: Antoine Labour <piman@chromium.org>
Reviewed-by: Klaus Weidner <klausw@chromium.org>
Commit-Queue: Biao She <bshe@chromium.org>
Cr-Commit-Position: refs/heads/master@{#554831}

ui/gl/BUILD.gn

@@ -216,12 +216,17 @@ component("gl") {
       }
     }
 
-    if (is_posix || is_fuchsia) {
+    if (is_posix && !is_fuchsia) {
       # Windows has USE_EGL but doesn't support base::FileDescriptor
+      # Fuchsia is excluded due to a libsync dependency and because it's
+      # unknown if the required EGL_ANDROID_native_fence_sync extension works
+      # there. If it does and there's a use case, this could be revisited.
       sources += [
         "gl_fence_android_native_fence_sync.cc",
         "gl_fence_android_native_fence_sync.h",
       ]
+
+      deps += [ "//third_party/libsync" ]
     }
   }
   if (is_mac || use_egl) {

ui/gl/DEPS

 include_rules = [
   "+components/crash/core/common/crash_key.h",  # Remove after fixing crbug.com/724999.
   "+third_party/khronos",
+  "+third_party/libsync",
   "+third_party/skia",
   "+ui/events",
   "+ui/base/x",

ui/gl/gl_fence.cc

@@ -18,7 +18,7 @@
 #include "ui/gl/gl_fence_apple.h"
 #endif
 
-#if defined(USE_EGL) && defined(OS_POSIX)
+#if defined(USE_EGL) && defined(OS_POSIX) && !defined(OS_FUCHSIA)
 #include "ui/gl/gl_fence_android_native_fence_sync.h"
 #include "ui/gl/gl_surface_egl.h"
 #endif
@@ -92,7 +92,7 @@ void GLFence::Invalidate() {
 }
 
 bool GLFence::IsGpuFenceSupported() {
-#if defined(USE_EGL) && defined(OS_POSIX)
+#if defined(USE_EGL) && defined(OS_POSIX) && !defined(OS_FUCHSIA)
   return gl::GLSurfaceEGL::IsAndroidNativeFenceSyncSupported();
 #else
   return false;
@@ -105,7 +105,7 @@ std::unique_ptr<GLFence> GLFence::CreateFromGpuFence(
   DCHECK(IsGpuFenceSupported());
   switch (gpu_fence.GetGpuFenceHandle().type) {
     case gfx::GpuFenceHandleType::kAndroidNativeFenceSync:
-#if defined(USE_EGL) && defined(OS_POSIX)
+#if defined(USE_EGL) && defined(OS_POSIX) && !defined(OS_FUCHSIA)
       return GLFenceAndroidNativeFenceSync::CreateFromGpuFence(gpu_fence);
 #else
       NOTREACHED();
@@ -120,7 +120,7 @@ std::unique_ptr<GLFence> GLFence::CreateFromGpuFence(
 // static
 std::unique_ptr<GLFence> GLFence::CreateForGpuFence() {
   DCHECK(IsGpuFenceSupported());
-#if defined(USE_EGL) && defined(OS_POSIX)
+#if defined(USE_EGL) && defined(OS_POSIX) && !defined(OS_FUCHSIA)
   return GLFenceAndroidNativeFenceSync::CreateForGpuFence();
 #endif
   NOTREACHED();

ui/gl/gl_fence_android_native_fence_sync.cc

@@ -4,7 +4,12 @@
 
 #include "ui/gl/gl_fence_android_native_fence_sync.h"
 
+#include <sync/sync.h>
+
+#include "base/files/scoped_file.h"
+#include "base/logging.h"
 #include "base/memory/ptr_util.h"
+#include "base/time/time.h"
 #include "ui/gfx/gpu_fence_handle.h"
 #include "ui/gl/gl_surface_egl.h"
 
@@ -65,4 +70,37 @@ std::unique_ptr<gfx::GpuFence> GLFenceAndroidNativeFenceSync::GetGpuFence() {
   return std::make_unique<gfx::GpuFence>(handle);
 }
 
+base::TimeTicks GLFenceAndroidNativeFenceSync::GetStatusChangeTime() {
+  EGLint sync_fd = eglDupNativeFenceFDANDROID(display_, sync_);
+  if (sync_fd < 0)
+    return base::TimeTicks();
+
+  base::ScopedFD scoped_fd(sync_fd);
+
+  struct sync_fence_info_data* info;
+  info = sync_fence_info(scoped_fd.get());
+  if (!info)
+    return base::TimeTicks();
+
+  struct sync_pt_info* pt_info = nullptr;
+  pt_info = sync_pt_info(info, pt_info);
+  if (!pt_info)
+    return base::TimeTicks();
+
+  base::TimeTicks t = base::TimeTicks() +
+                      base::TimeDelta::FromNanoseconds(pt_info->timestamp_ns);
+
+  if (!sync_pt_info(info, pt_info)) {
+    // It is possible that multiple sync_pt_info could be extracted from
+    // sync_fence_info_data. We currently only handle one.
+    DLOG(WARNING) << "Ambiguous status change time. More than one result "
+                     "could be extracted";
+
+    return base::TimeTicks();
+  }
+
+  sync_fence_info_free(info);
+  return t;
+}
+
 }  // namespace gl

ui/gl/gl_fence_android_native_fence_sync.h

@@ -24,6 +24,10 @@ class GL_EXPORT GLFenceAndroidNativeFenceSync : public GLFenceEGL {
 
   std::unique_ptr<gfx::GpuFence> GetGpuFence() override;
 
+  // This is a best effort to get status change time. It might fail and a null
+  // TimeTicks will be returned in that case.
+  base::TimeTicks GetStatusChangeTime();
+
  private:
   GLFenceAndroidNativeFenceSync();
   static std::unique_ptr<GLFenceAndroidNativeFenceSync> CreateInternal(