Update Context Client Visibility to use Scoped Pattern

cc/trees/layer_tree_host_unittest.cc

Index: cc/trees/layer_tree_host_unittest.cc
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index 129aeca9bf265c698e797cdc0d685f236ed4aa78..d4212e48285edea76899dbe5826bc1dbf0b41852 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -452,7 +452,10 @@ class LayerTreeHostFreeWorkerContextResourcesTest : public LayerTreeHostTest {
 
     // At init, visibility is set to true and we will call
     // SetAggressivelyFreeResources(false).
-    EXPECT_CALL(*mock_context_support_ptr_, SetClientVisible(0, true));
+    EXPECT_CALL(*mock_context_support_ptr_, ClientBecameVisible())
+        .WillOnce(
+            ::testing::Invoke(mock_context_support_ptr_,
+                              &MockContextSupport::SuperClientBecameVisible));
     EXPECT_CALL(*mock_context_support_ptr_, AnyClientsVisible())
         .WillOnce(::testing::Return(true));
     EXPECT_CALL(*mock_context_support_ptr_,
@@ -479,7 +482,10 @@ class LayerTreeHostFreeWorkerContextResourcesTest : public LayerTreeHostTest {
 
     // While running, visibility is set to false, and we will call
     // DeleteCachedResources and SetAggressivelyFreeResources(true).
-    EXPECT_CALL(*mock_context_support_ptr_, SetClientVisible(0, false));
+    EXPECT_CALL(*mock_context_support_ptr_, ClientBecameNotVisible_(_))
+        .WillOnce(::testing::Invoke(
+            mock_context_support_ptr_,
+            &MockContextSupport::SuperClientBecameNotVisible));
     EXPECT_CALL(*mock_context_support_ptr_, AnyClientsVisible())
         .WillOnce(::testing::Return(false));
     EXPECT_CALL(*mock_context_provider_ptr_, DeleteCachedResources());
@@ -509,11 +515,27 @@ class LayerTreeHostFreeWorkerContextResourcesTest : public LayerTreeHostTest {
 
   class MockContextSupport : public TestContextSupport {
    public:
+    using VisibilityToken = std::unique_ptr<ScopedVisibility>;
     MockContextSupport() {}
     MOCK_METHOD1(SetAggressivelyFreeResources,
                  void(bool aggressively_free_resources));
-    MOCK_METHOD2(SetClientVisible, void(int client_id, bool is_visible));
+    MOCK_METHOD0(ClientBecameVisible, VisibilityToken());
+    MOCK_METHOD1(ClientBecameNotVisible_,
+                 void(VisibilityToken& visibility));  // NOLINT
     MOCK_CONST_METHOD0(AnyClientsVisible, bool());
+
+    // Wrapper to allow mocking w/ move-only type.
+    void ClientBecameNotVisible(VisibilityToken visibility) override {
+      ClientBecameNotVisible_(visibility);
+    }
+
+    // Wrappers to allow forwarding to super class implementation.
+    void SuperClientBecameNotVisible(VisibilityToken& visibility) {  // NOLINT
+      TestContextSupport::ClientBecameNotVisible(std::move(visibility));
+    }
+    VisibilityToken SuperClientBecameVisible() {
+      return TestContextSupport::ClientBecameVisible();
+    }
   };
 
   MockContextSupport* mock_context_support_ptr_;