NotifyAllTileTasksCompleted for synchronous renderer compositor

This change ensures that in cases where no work is enqueued on the tile manager when we background, the NotifyAllTileTasksCompleted signal is still delivered.

Added a test to ensure that we call the appropriate callback in the synchronous renderer case.

BUG=505495
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1228323004

Cr-Commit-Position: refs/heads/master@{#338589}

1 files changed, 16 insertions, 0 deletions

diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index 6c3ae9e..6d9c9c6 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -353,6 +353,22 @@ class LayerTreeHostFreeWorkerContextResourcesOnZeroMemoryLimit
 SINGLE_AND_MULTI_THREAD_TEST_F(
     LayerTreeHostFreeWorkerContextResourcesOnZeroMemoryLimit);
 
+// Test if the LTH successfully frees resources on the worker context when
+// hard memory limit is set to zero while using a synchronous compositor (like
+// Android WebView).
+class LayerTreeHostFreeWorkerContextResourcesOnZeroMemoryLimitSynchronous
+    : public LayerTreeHostFreeWorkerContextResourcesOnZeroMemoryLimit {
+ public:
+  void InitializeSettings(LayerTreeSettings* settings) override {
+    LayerTreeHostFreeWorkerContextResourcesTest::InitializeSettings(settings);
+    settings->use_external_begin_frame_source = true;
+    settings->using_synchronous_renderer_compositor = true;
+  }
+};
+
+SINGLE_AND_MULTI_THREAD_TEST_F(
+    LayerTreeHostFreeWorkerContextResourcesOnZeroMemoryLimitSynchronous);
+
 // Two setNeedsCommits in a row should lead to at least 1 commit and at least 1
 // draw with frame 0.
 class LayerTreeHostTestSetNeedsCommit1 : public LayerTreeHostTest {