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

Source/platform/graphics/gpu/DrawingBufferTest.cpp

Index: Source/platform/graphics/gpu/DrawingBufferTest.cpp
diff --git a/Source/platform/graphics/gpu/DrawingBufferTest.cpp b/Source/platform/graphics/gpu/DrawingBufferTest.cpp
index c9195fac582fc5b234c889d540b0916711a54394..767fcfdbff1c091bbb348c01d841da384e902627 100644
--- a/Source/platform/graphics/gpu/DrawingBufferTest.cpp
+++ b/Source/platform/graphics/gpu/DrawingBufferTest.cpp
@@ -620,22 +620,4 @@
     }
 }
 
-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());
-
-    m_drawingBuffer->beginDestruction();
-}
-
 } // namespace