cc: Make OutputSurface::BindToClient pure virtual and not return bool

cc/test/layer_tree_pixel_test.cc

Index: cc/test/layer_tree_pixel_test.cc
diff --git a/cc/test/layer_tree_pixel_test.cc b/cc/test/layer_tree_pixel_test.cc
index 871573ea05371d3365f5759741265e0303f02753..ce021b94a6d4bdc60f6b6911345a59136fff685e 100644
--- a/cc/test/layer_tree_pixel_test.cc
+++ b/cc/test/layer_tree_pixel_test.cc
@@ -69,13 +69,16 @@ LayerTreePixelTest::CreateDisplayOutputSurfaceOnThread(
     scoped_refptr<ContextProvider> compositor_context_provider) {
   std::unique_ptr<PixelTestOutputSurface> display_output_surface;
   if (test_type_ == PIXEL_TEST_GL) {
+    // Pixel tests use a separate context for the Display to more closely
+    // mimic texture transport from the renderer process to the Display
+    // compositor.
+    auto display_context_provider =
+        make_scoped_refptr(new TestInProcessContextProvider(nullptr));
+    display_context_provider->BindToCurrentThread();
+
     bool flipped_output_surface = false;
     display_output_surface = base::MakeUnique<PixelTestOutputSurface>(
-        // Pixel tests use a separate context for the Display to more closely
-        // mimic texture transport from the renderer process to the Display
-        // compositor.
-        make_scoped_refptr(new TestInProcessContextProvider(nullptr)),
-        flipped_output_surface);
+        std::move(display_context_provider), flipped_output_surface);
   } else {
     display_output_surface = base::MakeUnique<PixelTestOutputSurface>(
         base::MakeUnique<SoftwareOutputDevice>());