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 d0635a7bf3d47827828968cecab0b241628a24de..c0f7b47cee443b79b062511e60bdfbdce23e2453 100644
--- a/cc/test/layer_tree_pixel_test.cc
+++ b/cc/test/layer_tree_pixel_test.cc
@@ -246,7 +246,8 @@ scoped_ptr<SkBitmap> LayerTreePixelTest::CopyTextureMailboxToBitmap(
   gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
   gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
   gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
-  gl->ConsumeTextureCHROMIUM(texture_mailbox.target(), texture_mailbox.data());
+  gl->ConsumeTextureCHROMIUM(texture_mailbox.target(),
+                             texture_mailbox.mailbox().name);
   gl->BindTexture(GL_TEXTURE_2D, 0);
 
   GLuint fbo = 0;
@@ -368,7 +369,7 @@ void LayerTreePixelTest::CopyBitmapToTextureMailboxAsTexture(
   gl->BindTexture(GL_TEXTURE_2D, 0);
   uint32 sync_point = gl->InsertSyncPointCHROMIUM();
 
-  *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),