cc: Remove some unnecessary const scoped_refptr&.

cc/output/renderer_unittest.cc

Index: cc/output/renderer_unittest.cc
diff --git a/cc/output/renderer_unittest.cc b/cc/output/renderer_unittest.cc
index 3c8b0b8cff4787d58f6cdec9cc0e9988e28eddcb..1648aece04ac299f3d002de4390c42f2acdbc8a3 100644
--- a/cc/output/renderer_unittest.cc
+++ b/cc/output/renderer_unittest.cc
@@ -18,8 +18,7 @@ namespace {
 
 class TestOutputSurface : public OutputSurface {
  public:
-  explicit TestOutputSurface(
-      const scoped_refptr<ContextProvider>& context_provider);
+  explicit TestOutputSurface(scoped_refptr<ContextProvider> context_provider);
   ~TestOutputSurface() override;
 
   // OutputSurface implementation
@@ -27,9 +26,8 @@ class TestOutputSurface : public OutputSurface {
 };
 
 TestOutputSurface::TestOutputSurface(
-    const scoped_refptr<ContextProvider>& context_provider)
-    : OutputSurface(context_provider) {
-}
+    scoped_refptr<ContextProvider> context_provider)
+    : OutputSurface(std::move(context_provider)) {}
 
 TestOutputSurface::~TestOutputSurface() {
 }