ozone/platform/wayland: Ensure that globals are bound with supported versions

ui/ozone/platform/wayland/wayland_display.cc

Index: ui/ozone/platform/wayland/wayland_display.cc
diff --git a/ui/ozone/platform/wayland/wayland_display.cc b/ui/ozone/platform/wayland/wayland_display.cc
index 488754a480fbff807923f5741126b69ec3f2e3b7..3ad93f8b94fcd1768ba68b7a532204493e059a47 100644
--- a/ui/ozone/platform/wayland/wayland_display.cc
+++ b/ui/ozone/platform/wayland/wayland_display.cc
@@ -12,6 +12,11 @@
 static_assert(XDG_SHELL_VERSION_CURRENT == 5, "Unsupported xdg-shell version");
 
 namespace ui {
+namespace {
+const uint32_t kMaxCompositorVersion = 4;
+const uint32_t kMaxShmVersion = 1;
+const uint32_t kMaxXdgShellVersion = 1;
+}  // namespace
 
 WaylandDisplay::WaylandDisplay() {}
 
@@ -103,15 +108,18 @@ void WaylandDisplay::Global(void* data,
 
   WaylandDisplay* display = static_cast<WaylandDisplay*>(data);
   if (!display->compositor_ && strcmp(interface, "wl_compositor") == 0) {
-    display->compositor_ = wl::Bind<wl_compositor>(registry, name, version);
+    display->compositor_ = wl::Bind<wl_compositor>(
+        registry, name, std::min(version, kMaxCompositorVersion));

[spang, 2016/02/17 23:25:03]

Should

version < 4

be an error? Or is the code actually prepared to deal with old servers?

Same for the others. If the server doesn't support the one you tested against,
are we expecting that to actually work?

     if (!display->compositor_)
       LOG(ERROR) << "Failed to bind to wl_compositor global";
   } else if (!display->shm_ && strcmp(interface, "wl_shm") == 0) {
-    display->shm_ = wl::Bind<wl_shm>(registry, name, version);
+    display->shm_ =
+        wl::Bind<wl_shm>(registry, name, std::min(version, kMaxShmVersion));
     if (!display->shm_)
       LOG(ERROR) << "Failed to bind to wl_shm global";
   } else if (!display->shell_ && strcmp(interface, "xdg_shell") == 0) {
-    display->shell_ = wl::Bind<xdg_shell>(registry, name, version);
+    display->shell_ = wl::Bind<xdg_shell>(
+        registry, name, std::min(version, kMaxXdgShellVersion));
     if (!display->shell_) {
       LOG(ERROR) << "Failed to  bind to xdg_shell global";
       return;