Reland r206537 - cc: Don't return mailboxes if the TextureLayer is removed from the tree.

cc/layers/texture_layer_unittest.cc

 // Copyright 2012 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 "cc/layers/texture_layer.h"
 
 #include <string>
 
 #include "base/callback.h"
 #include "cc/base/thread.h"
@@ skipping 395 matching lines @@
         break;
       case 6:
         // Old mailbox was released, task was posted, but won't execute
         // until this DidCommit returns.
         // TODO(piman): fix this.
         EXPECT_EQ(3, callback_count_);
         layer_tree_host()->SetNeedsCommit();
         break;
       case 7:
         EXPECT_EQ(4, callback_count_);
+        // Restore a mailbox for the next step.
+        SetMailbox('5');
+        break;
+      case 8:
+        // Case #5: remove layer from tree. Callback should *not* be called, the
+        // mailbox is returned to the main thread.
+        EXPECT_EQ(4, callback_count_);
+        layer_->RemoveFromParent();
+        break;
+      case 9:
+        // Mailbox was released to the main thread, task was posted, but won't
+        // execute until this DidCommit returns.
+        // TODO(piman): fix this.
+        EXPECT_EQ(4, callback_count_);
+        layer_tree_host()->SetNeedsCommit();
+        break;
+      case 10:
+        EXPECT_EQ(4, callback_count_);
+        // Resetting the mailbox will call the callback now.
+        layer_->SetTextureMailbox(TextureMailbox());
+        EXPECT_EQ(5, callback_count_);
         EndTest();
         break;
       default:
         NOTREACHED();
         break;
     }
   }
 
   virtual void AfterTest() OVERRIDE {}
 
@@ skipping 291 matching lines @@
   base::Lock lock_;
   unsigned expected_used_textures_on_commit_;
 };
 
 // The TextureLayerClient does not use mailboxes, so can't use a delegating
 // renderer.
 SINGLE_AND_MULTI_THREAD_DIRECT_RENDERER_TEST_F(TextureLayerClientTest);
 
 }  // namespace
 }  // namespace cc