Make callers of CommandLine use it via the base:: namespace.

Covers content/.

BUG=422426
TEST=none
[email protected]

Review URL: https://codereview.chromium.org/803813003

Cr-Commit-Position: refs/heads/master@{#309496}
diff --git a/content/browser/transition_request_manager_unittest.cc b/content/browser/transition_request_manager_unittest.cc
index 31a78f4..02978b7e4 100644
--- a/content/browser/transition_request_manager_unittest.cc
+++ b/content/browser/transition_request_manager_unittest.cc
@@ -16,7 +16,7 @@
  public:
   TransitionRequestManagerTest()
       : thread_bundle_(TestBrowserThreadBundle::IO_MAINLOOP) {
-    CommandLine::ForCurrentProcess()->AppendSwitch(
+    base::CommandLine::ForCurrentProcess()->AppendSwitch(
         switches::kEnableExperimentalWebPlatformFeatures);
   }