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

Source/platform/graphics/Canvas2DLayerBridge.cpp

Index: Source/platform/graphics/Canvas2DLayerBridge.cpp
diff --git a/Source/platform/graphics/Canvas2DLayerBridge.cpp b/Source/platform/graphics/Canvas2DLayerBridge.cpp
index 5e2f83c293a99350ea6c8b818abf25026147f5bf..f7cea3dccab7dd43b28a1749ebed49b6df9b0d48 100644
--- a/Source/platform/graphics/Canvas2DLayerBridge.cpp
+++ b/Source/platform/graphics/Canvas2DLayerBridge.cpp
@@ -489,18 +489,46 @@ Canvas2DLayerBridge::MailboxInfo* Canvas2DLayerBridge::createMailboxInfo() {
     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()) {
@@ -509,8 +537,6 @@ void Canvas2DLayerBridge::mailboxReleased(const blink::WebExternalTextureMailbox
                 ASSERT(!m_destructionInProgress);
                 Canvas2DLayerManager::get().layerTransientResourceAllocationChanged(this);
             }
-            ASSERT(mailboxInfo->m_parentLayerBridge.get() == this);
-            mailboxInfo->m_parentLayerBridge.clear();
             return;
         }
     }