Add a full Blimp integration test.

blimp/client/core/compositor/blimp_compositor_manager.cc

Index: blimp/client/core/compositor/blimp_compositor_manager.cc
diff --git a/blimp/client/core/compositor/blimp_compositor_manager.cc b/blimp/client/core/compositor/blimp_compositor_manager.cc
index 6dd60092d51401616696a05f8bcf220d9fb0abc2..a8c9c66c5fb7d347e6672b56711e0ae9f741f533 100644
--- a/blimp/client/core/compositor/blimp_compositor_manager.cc
+++ b/blimp/client/core/compositor/blimp_compositor_manager.cc
@@ -43,6 +43,16 @@ bool BlimpCompositorManager::OnTouchEvent(const ui::MotionEvent& motion_event) {
   return false;
 }
 
+void BlimpCompositorManager::NotifyWhenDonePendingCommits(
+    base::Closure callback) {
+  if (!active_compositor_ || !visible_) {
+    callback.Run();
+    return;
+  }
+
+  active_compositor_->NotifyWhenDonePendingCommits(callback);
+}
+
 std::unique_ptr<BlimpCompositor> BlimpCompositorManager::CreateBlimpCompositor(
     int render_widget_id,
     BlimpCompositorDependencies* compositor_dependencies,