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..60e05784aaba7c7286f23bbe16ad2cd2dadba6c7 100644
--- a/Source/platform/graphics/gpu/DrawingBuffer.cpp
+++ b/Source/platform/graphics/gpu/DrawingBuffer.cpp
@@ -276,8 +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)
 {
+    // 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;