Update Context Client Visibility to use Scoped Pattern

gpu/command_buffer/client/context_support.h

Index: gpu/command_buffer/client/context_support.h
diff --git a/gpu/command_buffer/client/context_support.h b/gpu/command_buffer/client/context_support.h
index 99e94045326adf8b4abcd2acd1570f085789ee9d..20f9efe28d073fde938b8b17bd6dce39917cac79 100644
--- a/gpu/command_buffer/client/context_support.h
+++ b/gpu/command_buffer/client/context_support.h
@@ -17,6 +17,7 @@ class RectF;
 
 namespace gpu {
 
+class ScopedContextClientVisibility;

[danakj, 2016/08/18 21:39:44]

remove?

[ericrk, 2016/08/19 17:23:19]

Done.

 struct SyncToken;
 
 class ContextSupport {
@@ -56,8 +57,10 @@ class ContextSupport {
   virtual void SetErrorMessageCallback(
       const base::Callback<void(const char*, int32_t)>& callback) = 0;
 
-  // Called when a client of the context has changed visibility.
-  virtual void SetClientVisible(int client_id, bool is_visible) = 0;
+  class ScopedVisibility {};
+  virtual std::unique_ptr<ScopedVisibility> ClientBecameVisible() = 0;
+  virtual void ClientBecameNotVisible(
+      std::unique_ptr<ScopedVisibility> visibility) = 0;
   virtual bool AnyClientsVisible() const = 0;
 
  protected: