diff --git a/cc/tiles/image_manager.cc b/cc/tiles/image_manager.cc
index bec8ca2061ea08..04d4e61a9bbd3f 100644
--- a/cc/tiles/image_manager.cc
+++ b/cc/tiles/image_manager.cc
@@ -11,14 +11,17 @@ ImageManager::~ImageManager() = default;
 
 void ImageManager::SetImageDecodeController(ImageDecodeController* controller) {
   // We can only switch from null to non-null and back.
-  DCHECK(controller || controller_);
-  DCHECK(!controller || !controller_);
+  // CHECK to debug crbug.com/650234.
+  CHECK(controller || controller_);
+  CHECK(!controller || !controller_);
 
   if (!controller) {
     SetPredecodeImages(std::vector<DrawImage>(),
                        ImageDecodeController::TracingInfo());
   }
   controller_ = controller;
+  // Debugging information for crbug.com/650234.
+  ++num_times_controller_was_set_;
 }
 
 void ImageManager::GetTasksForImagesAndRef(
@@ -41,7 +44,8 @@ void ImageManager::GetTasksForImagesAndRef(
 }
 
 void ImageManager::UnrefImages(const std::vector<DrawImage>& images) {
-  DCHECK(controller_);
+  // Debugging information for crbug.com/650234.
+  CHECK(controller_) << num_times_controller_was_set_;
   for (auto image : images)
     controller_->UnrefImage(image);
 }
diff --git a/cc/tiles/image_manager.h b/cc/tiles/image_manager.h
index 046e0948e8bda2..13940a81d3fbe6 100644
--- a/cc/tiles/image_manager.h
+++ b/cc/tiles/image_manager.h
@@ -36,6 +36,9 @@ class CC_EXPORT ImageManager {
   ImageDecodeController* controller_ = nullptr;
   std::vector<DrawImage> predecode_locked_images_;
 
+  // Debugging information for crbug.com/650234.
+  size_t num_times_controller_was_set_ = 0;
+
   DISALLOW_COPY_AND_ASSIGN(ImageManager);
 };
 
diff --git a/cc/tiles/tile_manager.cc b/cc/tiles/tile_manager.cc
index 6388c8877b7cd8..ea9b32c3523f66 100644
--- a/cc/tiles/tile_manager.cc
+++ b/cc/tiles/tile_manager.cc
@@ -346,11 +346,11 @@ void TileManager::FinishTasksAndCleanUp() {
 
   raster_buffer_provider_->Shutdown();
 
+  tile_task_manager_->CheckForCompletedTasks();
+
   // Now that all tasks have been finished, we can clear any |orphan_tasks_|.
   orphan_tasks_.clear();
 
-  tile_task_manager_->CheckForCompletedTasks();
-
   FreeResourcesForReleasedTiles();
   CleanUpReleasedTiles();