Fix race conditions in window snapshot code.

Use LatencyInfo to track when a rendered frame reaches the screen.
Only tested so far on Linux with single-threaded compositor. Must be
tested with Telemetry's GpuTabTest.testScreenshot test on all of
Windows, Mac and Linux with the compositor disabled, enabled and
single-threaded, and enabled and multi-threaded.

BUG=256848

Review URL: https://codereview.chromium.org/23694031

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228652 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 14 insertions, 0 deletions

diff --git a/cc/test/layer_tree_test.cc b/cc/test/layer_tree_test.cc
index 87fcb54..6a7cf50 100644
--- a/cc/test/layer_tree_test.cc
+++ b/cc/test/layer_tree_test.cc
@@ -414,6 +414,13 @@ void LayerTreeTest::PostSetVisibleToMainThread(bool visible) {
                  visible));
 }
 
+void LayerTreeTest::PostSetNextCommitForcesRedrawToMainThread() {
+  proxy()->MainThreadTaskRunner()->PostTask(
+      FROM_HERE,
+      base::Bind(&LayerTreeTest::DispatchSetNextCommitForcesRedraw,
+                 main_thread_weak_ptr_));
+}
+
 void LayerTreeTest::DoBeginTest() {
   client_ = LayerTreeHostClientForTesting::Create(this);
 
@@ -558,6 +565,13 @@ void LayerTreeTest::DispatchSetVisible(bool visible) {
     ScheduleComposite();
 }
 
+void LayerTreeTest::DispatchSetNextCommitForcesRedraw() {
+  DCHECK(!proxy() || proxy()->IsMainThread());
+
+  if (layer_tree_host_)
+    layer_tree_host_->SetNextCommitForcesRedraw();
+}
+
 void LayerTreeTest::DispatchComposite() {
   scheduled_ = false;