blimp: Add logging for compositor and render widget feature.

blimp/client/feature/compositor/blimp_compositor_manager.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "blimp/client/feature/compositor/blimp_compositor_manager.h"
 
 #include "base/lazy_instance.h"
 #include "blimp/client/feature/compositor/blimp_layer_tree_settings.h"
 #include "blimp/common/compositor/blimp_image_serialization_processor.h"
 #include "blimp/common/compositor/blimp_task_graph_runner.h"
@@ skipping 71 matching lines @@
   compositors_[render_widget_id] = CreateBlimpCompositor(render_widget_id,
                                                          this);
 }
 
 void BlimpCompositorManager::OnRenderWidgetInitialized(int render_widget_id) {
   if (active_compositor_ &&
       active_compositor_->render_widget_id() == render_widget_id)
     return;
 
   if (active_compositor_) {
+    VLOG(1) << "Hiding currently active compositor for render widget: "
+            << active_compositor_->render_widget_id();
     active_compositor_->SetVisible(false);
     active_compositor_->ReleaseAcceleratedWidget();
   }
 
   active_compositor_ = GetCompositor(render_widget_id);
   DCHECK(active_compositor_);
 
   active_compositor_->SetVisible(visible_);
   active_compositor_->SetAcceleratedWidget(window_);
 }
@@ skipping 89 matching lines @@
 
 BlimpCompositor* BlimpCompositorManager::GetCompositor(int render_widget_id) {
   CompositorMap::const_iterator it = compositors_.find(render_widget_id);
   if (it == compositors_.end())
     return nullptr;
   return it->second.get();
 }
 
 }  // namespace client
 }  // namespace blimp