cc: Remove the unused compositor thread variable and interface.

content/child/child_discardable_shared_memory_manager_browsertest.cc

Index: content/child/child_discardable_shared_memory_manager_browsertest.cc
diff --git a/content/child/child_discardable_shared_memory_manager_browsertest.cc b/content/child/child_discardable_shared_memory_manager_browsertest.cc
index 1ffa01ef7a0093fd5e546600dd1c9104346de2c2..18598fbdbb0e3818ab0574a1ec32069178f952c9 100644
--- a/content/child/child_discardable_shared_memory_manager_browsertest.cc
+++ b/content/child/child_discardable_shared_memory_manager_browsertest.cc
@@ -15,6 +15,10 @@
 
 namespace content {
 
+// ChromeOS does not do software compositing, so kDisableGpu is not available
+// there.
+#if !defined(OS_CHROMEOS)
+
 class ChildDiscardableSharedMemoryManagerBrowserTest
     : public ContentBrowserTest {
  public:
@@ -118,4 +122,6 @@ IN_PROC_BROWSER_TEST_F(ChildDiscardableSharedMemoryManagerBrowserTest,
   }
 }
 
+#endif  // !OS_CHROMEOS
+
 }  // content