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 3085150214a31af1a96469156024c003667e943c..ccf1a2ba6bad2d9cd207a1ef1ff320ccf2e7ffce 100644
--- a/blimp/client/core/compositor/blimp_compositor_manager.cc
+++ b/blimp/client/core/compositor/blimp_compositor_manager.cc
@@ -45,6 +45,16 @@ 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,