WebGL: Free temporary GPU resources held by inactive or hidden WebGL.

Source/platform/graphics/gpu/DrawingBufferTest.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 602 matching lines @@
             EXPECT_NE(trackingContext->stencilAttachment(), trackingContext->depthAttachment());
         } else {
             EXPECT_EQ(0u, trackingContext->stencilAttachment());
             EXPECT_EQ(0u, trackingContext->depthAttachment());
         }
 
         drawingBuffer->beginDestruction();
     }
 }
 
+TEST_F(DrawingBufferTest, verifySetIsHiddenProperlyAffectsMailboxes)
+{
+    blink::WebExternalTextureMailbox mailbox;
+
+    // Produce mailboxes.
+    m_drawingBuffer->markContentsChanged();
+    EXPECT_TRUE(m_drawingBuffer->prepareMailbox(&mailbox, 0));
+
+    unsigned waitSyncPoint = webContext()->insertSyncPoint();
+    mailbox.syncPoint = waitSyncPoint;
+    m_drawingBuffer->setIsHidden(true);
+    m_drawingBuffer->mailboxReleased(mailbox);
+    // m_drawingBuffer deletes mailbox immediately when hidden.
+    EXPECT_EQ(waitSyncPoint, webContext()->mostRecentlyWaitedSyncPoint());
+

[dshwang, 2014/07/09 17:40:54]

Remove EXPECT_FALSE(m_drawingBuffer->prepareMailbox(&mailbox, 0)); because I add
ASSERT in prepareMailbox()

+    m_drawingBuffer->beginDestruction();
+}
+
 } // namespace