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

Source/platform/graphics/Canvas2DLayerBridge.cpp

 /*
  * Copyright (C) 2012 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 471 matching lines @@
     // means there is a problem.
     // For the single-threaded case, this value needs to be at least
     // kMaxSwapBuffersPending+1 (in render_widget.h).
     // Because of crbug.com/247874, it needs to be kMaxSwapBuffersPending+2.
     // TODO(piman): fix this.
     ASSERT(m_mailboxes.size() <= 4);
     ASSERT(mailboxInfo < m_mailboxes.end());
     return mailboxInfo;
 }
 
-void Canvas2DLayerBridge::mailboxReleased(const blink::WebExternalTextureMailbox& mailbox)
+void Canvas2DLayerBridge::mailboxReleased(const blink::WebExternalTextureMailbox& mailbox, bool lostResource)
 {
     freeReleasedMailbox(); // Never have more than one mailbox in the released state.
+    bool contextLost = m_contextProvider->context3d()->isContextLost() || !m_isSurfaceValid;
     Vector<MailboxInfo>::iterator mailboxInfo;
     for (mailboxInfo = m_mailboxes.begin(); mailboxInfo < m_mailboxes.end(); ++mailboxInfo) {
         if (nameEquals(mailboxInfo->m_mailbox, mailbox)) {
             mailboxInfo->m_mailbox.syncPoint = mailbox.syncPoint;
             ASSERT(mailboxInfo->m_status == MailboxInUse);
-            mailboxInfo->m_status = MailboxReleased;
             // Trigger Canvas2DLayerBridge self-destruction if this is the
             // last live mailbox and the layer bridge is not externally
             // referenced.
+            ASSERT(mailboxInfo->m_parentLayerBridge.get() == this);
+            mailboxInfo->m_parentLayerBridge.clear();
+
+            if (contextLost) {
+                // No need to clean up the mailbox resource, but make sure the
+                // mailbox can also be reusable once the context is restored.
+                mailboxInfo->m_status = MailboxAvailable;
+                m_releasedMailboxInfoIndex = InvalidMailboxIndex;
+                Canvas2DLayerManager::get().layerTransientResourceAllocationChanged(this);
+                return;
+            }
+
+            // In case of the resource is lost, we need to delete the backing texture
+            // and remove the mailbox from list to avoid reusing it in future.
+            if (lostResource) {
+                if (mailboxInfo->m_image) {
+                    mailboxInfo->m_image->getTexture()->resetFlag(
+                        static_cast<GrTextureFlags>(GrTexture::kReturnToCache_FlagBit));
+                    mailboxInfo->m_image->getTexture()->textureParamsModified();
+                    mailboxInfo->m_image.clear();
+                }
+                size_t i = mailboxInfo - m_mailboxes.begin();
+                m_mailboxes.remove(i);
+                Canvas2DLayerManager::get().layerTransientResourceAllocationChanged(this);
+                return;

[Justin Novosad, 2014/07/15 16:12:03]

More readable if you put the code below inside an "else", instead of having a
"return" here. But that is just my personal opinion on style. Feel free to
ignore.

[Hongbo Min, 2014/07/16 01:32:20]

Done.

+            }
+
+            mailboxInfo->m_status = MailboxReleased;
             m_releasedMailboxInfoIndex = mailboxInfo - m_mailboxes.begin();
             m_framesSinceMailboxRelease = 0;
             if (isHidden()) {
                 freeReleasedMailbox();
             } else {
                 ASSERT(!m_destructionInProgress);
                 Canvas2DLayerManager::get().layerTransientResourceAllocationChanged(this);
             }
-            ASSERT(mailboxInfo->m_parentLayerBridge.get() == this);
-            mailboxInfo->m_parentLayerBridge.clear();
             return;
         }
     }
 }
 
 blink::WebLayer* Canvas2DLayerBridge::layer() const
 {
     ASSERT(!m_destructionInProgress);
     ASSERT(m_layer);
     return m_layer->layer();
@@ skipping 24 matching lines @@
 Canvas2DLayerBridge::MailboxInfo::MailboxInfo(const MailboxInfo& other) {
     // This copy constructor should only be used for Vector reallocation
     // Assuming 'other' is to be destroyed, we transfer m_image ownership
     // rather than do a refcount dance.
     memcpy(&m_mailbox, &other.m_mailbox, sizeof(m_mailbox));
     m_image = const_cast<MailboxInfo*>(&other)->m_image.release();
     m_status = other.m_status;
 }
 
 }