Fix LTHI shutdown crash when disabling vsync immediately

Before this, scheduler is destroyed after LTHI. Scheduler disables vsync
in its destructor, which when the notification is propagated immediately
from VSyncTimeSource (in Android WebView), it crashes in
ThreadProxy::RequestVSyncNotification because LTHI is already gone.

Fix by destroying scheduler before LTHI.

BUG=

Review URL: https://chromiumcodereview.appspot.com/15057006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@199513 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 23 insertions, 1 deletions

diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index 8be478e..4591f14 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -2318,6 +2318,28 @@ class LayerTreeHostTestVSyncNotification : public LayerTreeHostTest {
 
 MULTI_THREAD_TEST_F(LayerTreeHostTestVSyncNotification);
 
+class LayerTreeHostTestVSyncNotificationShutdownWhileEnabled
+    : public LayerTreeHostTest {
+ public:
+  virtual void InitializeSettings(LayerTreeSettings* settings) OVERRIDE {
+    settings->render_vsync_notification_enabled = true;
+    settings->synchronously_disable_vsync = true;
+  }
+
+  virtual void BeginTest() OVERRIDE { PostSetNeedsCommitToMainThread(); }
+
+  virtual void CommitCompleteOnThread(LayerTreeHostImpl* host_impl) OVERRIDE {
+    // The vsync notification is turned off now but will get enabled once we
+    // return. End test while it's enabled.
+    ImplThread()->PostTask(base::Bind(
+        &LayerTreeHostTestVSyncNotification::EndTest, base::Unretained(this)));
+  }
+
+  virtual void AfterTest() OVERRIDE {}
+};
+
+MULTI_THREAD_TEST_F(LayerTreeHostTestVSyncNotificationShutdownWhileEnabled);
+
 class LayerTreeHostTestInputDrivenRendering : public LayerTreeHostTest {
  public:
   virtual void InitializeSettings(LayerTreeSettings* settings) OVERRIDE {
diff --git a/cc/trees/thread_proxy.cc b/cc/trees/thread_proxy.cc
index 6ec17c8..86f4381 100644
--- a/cc/trees/thread_proxy.cc
+++ b/cc/trees/thread_proxy.cc
@@ -1218,8 +1218,8 @@ void ThreadProxy::LayerTreeHostClosedOnImplThread(CompletionEvent* completion) {
       layer_tree_host_impl_->resource_provider());
   layer_tree_host_impl_->EnableVSyncNotification(false);
   input_handler_client_on_impl_thread_.reset();
-  layer_tree_host_impl_.reset();
   scheduler_on_impl_thread_.reset();
+  layer_tree_host_impl_.reset();
   weak_factory_on_impl_thread_.InvalidateWeakPtrs();
   vsync_client_ = NULL;
   completion->Signal();