cc: Remove the unused compositor thread variable and interface.

content/browser/renderer_host/render_widget_host_view_browsertest.cc

Index: content/browser/renderer_host/render_widget_host_view_browsertest.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_browsertest.cc b/content/browser/renderer_host/render_widget_host_view_browsertest.cc
index 84d8176c366f90d1beb0f59267f8893410497d63..08a00e9da29efc87c7978ed63e7f197f48c8ff2a 100644
--- a/content/browser/renderer_host/render_widget_host_view_browsertest.cc
+++ b/content/browser/renderer_host/render_widget_host_view_browsertest.cc
@@ -942,16 +942,24 @@ IN_PROC_BROWSER_TEST_P(
                                 video_frame);
 }
 
+#if defined(OS_CHROMEOS)
+// On ChromeOS there is no software compositing.
+static const auto kTestCompositingModes = testing::Values(GL_COMPOSITING);
+#else
+static const auto kTestCompositingModes =
+    testing::Values(GL_COMPOSITING, SOFTWARE_COMPOSITING);
+#endif
+
 INSTANTIATE_TEST_CASE_P(GLAndSoftwareCompositing,
                         CompositingRenderWidgetHostViewBrowserTest,
-                        testing::Values(GL_COMPOSITING, SOFTWARE_COMPOSITING));
+                        kTestCompositingModes);
 INSTANTIATE_TEST_CASE_P(GLAndSoftwareCompositing,
                         CompositingRenderWidgetHostViewBrowserTestTabCapture,
-                        testing::Values(GL_COMPOSITING, SOFTWARE_COMPOSITING));
+                        kTestCompositingModes);
 INSTANTIATE_TEST_CASE_P(
     GLAndSoftwareCompositing,
     CompositingRenderWidgetHostViewBrowserTestTabCaptureHighDPI,
-    testing::Values(GL_COMPOSITING, SOFTWARE_COMPOSITING));
+    kTestCompositingModes);
 
 #endif  // !defined(OS_ANDROID) && !defined(OS_IOS)