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

gpu::Mailbox by itself can hold only a texture id, but in common usage it comes
with texture target and syncpoint information for cross-context sharing.  To
reduce repetition of this pattern, gpu::MailboxHolder holds:

* a gpu::Mailbox
* a GL texture target
* a syncpoint index

Refactor other classes to use a gpu::MailboxHolder instead of separate
gpu::Mailbox and associated state.

Syncpoints are created with uint32 indices; make sure all uses of syncpoints
use the appropriate type.

BUG=None
TEST=local build, unittests on CrOS snow, desktop Linux
TBR=piman@chromium.org, enn@chromium.orge, cevans@chromium.org, scherkus@chromium.org

Review URL: https://codereview.chromium.org/132233041

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248612 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 1 insertions, 3 deletions

diff --git a/cc/resources/transferable_resource.cc b/cc/resources/transferable_resource.cc
index 62f1bdb..e7e9e24 100644
--- a/cc/resources/transferable_resource.cc
+++ b/cc/resources/transferable_resource.cc
@@ -10,9 +10,7 @@ namespace cc {
 
 TransferableResource::TransferableResource()
     : id(0),
-      sync_point(0),
       format(RGBA_8888),
-      target(0),
       filter(0),
       is_software(false) {}
 
@@ -22,7 +20,7 @@ TransferableResource::~TransferableResource() {
 ReturnedResource TransferableResource::ToReturnedResource() const {
   ReturnedResource returned;
   returned.id = id;
-  returned.sync_point = sync_point;
+  returned.sync_point = mailbox_holder.sync_point;
   returned.count = 1;
   return returned;
 }