Replaced is_null() with is_valid in SurfaceId and related classes.

cc/layers/surface_layer_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdint.h>
 
 #include <set>
 #include <vector>
 
 #include "base/location.h"
@@ skipping 73 matching lines @@
   scoped_refptr<SurfaceLayer> layer2(SurfaceLayer::Create(
       base::Bind(&SatisfyCallback, &blank_change),
       base::Bind(&RequireCallback, &required_id, &required_seq)));
   layer2->SetSurfaceId(SurfaceId(kArbitraryFrameSinkId, LocalFrameId(1, 0)),
                        1.f, gfx::Size(1, 1));
   layer_tree_host2->GetSurfaceSequenceGenerator()->set_frame_sink_id(
       FrameSinkId(2, 2));
   layer_tree_host2->SetRootLayer(layer2);
 
   // Layers haven't been removed, so no sequence should be satisfied.
-  EXPECT_TRUE(blank_change.is_null());
+  EXPECT_FALSE(blank_change.is_valid());
 
   SurfaceSequence expected1(FrameSinkId(1, 1), 1u);
   SurfaceSequence expected2(FrameSinkId(2, 2), 1u);
 
   layer_tree_host2->SetRootLayer(nullptr);
   layer_tree_host2.reset();
 
   // Layer was removed so sequence from second LayerTreeHost should be
   // satisfied.
   EXPECT_TRUE(blank_change == expected2);
@@ skipping 106 matching lines @@
       EndTest();
     }
   }
 
   void AfterTest() override {
     EXPECT_TRUE(required_id_ ==
                 SurfaceId(kArbitraryFrameSinkId, LocalFrameId(1, 0)));
     EXPECT_EQ(1u, required_set_.size());
     // Sequence should have been satisfied through Swap, not with the
     // callback.
-    EXPECT_TRUE(satisfied_sequence_.is_null());
+    EXPECT_FALSE(satisfied_sequence_.is_valid());
   }
 };
 
 SINGLE_AND_MULTI_THREAD_TEST_F(SurfaceLayerSwapPromiseWithDraw);
 
 // Check that SurfaceSequence is sent through swap promise and resolved when
 // swap fails.
 class SurfaceLayerSwapPromiseWithoutDraw : public SurfaceLayerSwapPromise {
  public:
   SurfaceLayerSwapPromiseWithoutDraw() : SurfaceLayerSwapPromise() {}
@@ skipping 27 matching lines @@
     // Sequence should have been satisfied with the callback.
     EXPECT_TRUE(satisfied_sequence_ ==
                 SurfaceSequence(kArbitraryFrameSinkId, 1u));
   }
 };
 
 MULTI_THREAD_TEST_F(SurfaceLayerSwapPromiseWithoutDraw);
 
 }  // namespace
 }  // namespace cc