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

Source/platform/graphics/gpu/DrawingBuffer.cpp

Index: Source/platform/graphics/gpu/DrawingBuffer.cpp
diff --git a/Source/platform/graphics/gpu/DrawingBuffer.cpp b/Source/platform/graphics/gpu/DrawingBuffer.cpp
index 0ec4bf9179012c1217b92aa3362f4f7d02e1e9df..dfb2056ba6cb307076c70f302e01a21bb9195c14 100644
--- a/Source/platform/graphics/gpu/DrawingBuffer.cpp
+++ b/Source/platform/graphics/gpu/DrawingBuffer.cpp
@@ -276,9 +276,9 @@ bool DrawingBuffer::prepareMailbox(blink::WebExternalTextureMailbox* outMailbox,
     return true;
 }
 
-void DrawingBuffer::mailboxReleased(const blink::WebExternalTextureMailbox& mailbox)
+void DrawingBuffer::mailboxReleased(const blink::WebExternalTextureMailbox& mailbox, bool lostResource)
 {
-    if (m_destructionInProgress) {
+    if (m_destructionInProgress || m_context->isContextLost() || lostResource) {

[Ken Russell (switch to Gerrit), 2014/07/15 22:22:33]

Could you please add a new test to DrawingBufferTest.cpp which verifies the
behavior when mailboxRelease is called with lostResource=true?

         mailboxReleasedWhileDestructionInProgress(mailbox);
         return;
     }
@@ -354,6 +354,7 @@ void DrawingBuffer::deleteMailbox(const blink::WebExternalTextureMailbox& mailbo
             deleteChromiumImageForTexture(&m_textureMailboxes[i]->textureInfo);
 
             m_context->deleteTexture(m_textureMailboxes[i]->textureInfo.textureId);
+            m_textureMailboxes[i]->m_parentDrawingBuffer.clear();

[Ken Russell (switch to Gerrit), 2014/07/15 22:22:33]

Why is this necessary? The call to m_textureMailboxes.remove(i), below, should
cause the MailboxInfo to be deleted and its m_parentDrawingBuffer field cleared.

             m_textureMailboxes.remove(i);
             return;
         }