Add gpu::MailboxHolder to hold state for a gpu::Mailbox

cc/test/layer_tree_pixel_test.cc

Index: cc/test/layer_tree_pixel_test.cc
diff --git a/cc/test/layer_tree_pixel_test.cc b/cc/test/layer_tree_pixel_test.cc
index 3ad33dc5937ada330ca72632f629c18d8205d49a..cd0b6a2e80f544b2fb604c7557edbc100d23bcb8 100644
--- a/cc/test/layer_tree_pixel_test.cc
+++ b/cc/test/layer_tree_pixel_test.cc
@@ -241,7 +241,7 @@ scoped_ptr<SkBitmap> LayerTreePixelTest::CopyTextureMailboxToBitmap(
   context3d->texParameteri(
       GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
   context3d->consumeTextureCHROMIUM(texture_mailbox.target(),
-                                    texture_mailbox.data());
+                                    texture_mailbox.mailbox().name);
   context3d->bindTexture(GL_TEXTURE_2D, 0);
 
   unsigned fbo = context3d->createFramebuffer();
@@ -369,7 +369,7 @@ void LayerTreePixelTest::CopyBitmapToTextureMailboxAsTexture(
   context3d->bindTexture(GL_TEXTURE_2D, 0);
   uint32 sync_point = context3d->insertSyncPoint();
 
-  *texture_mailbox = TextureMailbox(mailbox, sync_point);
+  *texture_mailbox = TextureMailbox(mailbox, GL_TEXTURE_2D, sync_point);
   *release_callback = SingleReleaseCallback::Create(
       base::Bind(&LayerTreePixelTest::ReleaseTextureMailbox,
                  base::Unretained(this),