Let canvas decide how to handle the case of resource lost reported by client: 2D part

Source/platform/graphics/gpu/DrawingBuffer.cpp

 /*
  * Copyright (c) 2010, 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
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  *     * Redistributions in binary form must reproduce the above
@@ skipping 258 matching lines @@
     markLayerComposited();
 
     // set m_parentDrawingBuffer to make sure 'this' stays alive as long as it has live mailboxes
     ASSERT(!frontColorBufferMailbox->m_parentDrawingBuffer);
     frontColorBufferMailbox->m_parentDrawingBuffer = this;
     *outMailbox = frontColorBufferMailbox->mailbox;
     m_frontColorBuffer = frontColorBufferMailbox->textureInfo;
     return true;
 }
 
-void DrawingBuffer::mailboxReleased(const blink::WebExternalTextureMailbox& mailbox)
+void DrawingBuffer::mailboxReleased(const blink::WebExternalTextureMailbox& mailbox, bool lostResource)
 {
+    // TODO(hmin): Handle the resource lost case.

[dshwang, 2014/07/03 08:36:58]

I'm also curious about this case.
When compositor loses its context, it reports |lostResource|. However, mailbox
of WebGL is always created and deleted by WebGL.
Dose WebGL also lose its context always when compositor loses context?

In addition, this callback releases mailbox as follows;
 WaitSyncPoint(sync_point)
 DeleteTexture(texture)
When WebGL loses context, above operations become no-op, right?

[Hongbo Min, 2014/07/03 09:11:19]

Thanks for your comments! The CL is updated with the webgl handling.

     if (m_destructionInProgress) {
         mailboxReleasedWhileDestructionInProgress(mailbox);
         return;
     }
 
     for (size_t i = 0; i < m_textureMailboxes.size(); i++) {
         RefPtr<MailboxInfo> mailboxInfo = m_textureMailboxes[i];
         if (nameEquals(mailboxInfo->mailbox, mailbox)) {
             mailboxInfo->mailbox.syncPoint = mailbox.syncPoint;
             ASSERT(mailboxInfo->m_parentDrawingBuffer.get() == this);
@@ skipping 772 matching lines @@
 void DrawingBuffer::deleteChromiumImageForTexture(TextureInfo* info)
 {
     if (info->imageId) {
         m_context->releaseTexImage2DCHROMIUM(GL_TEXTURE_2D, info->imageId);
         m_context->destroyImageCHROMIUM(info->imageId);
         info->imageId = 0;
     }
 }
 
 } // namespace WebCore