test_runner: Move three Mock* files into content namespace.

content/shell/renderer/test_runner/MockColorChooser.cpp

Index: content/shell/renderer/test_runner/MockColorChooser.cpp
diff --git a/content/shell/renderer/test_runner/MockColorChooser.cpp b/content/shell/renderer/test_runner/MockColorChooser.cpp
index fbd6faaf0923b382fa666830279fdc48033c6602..c9321fc6d73e5af6d7cd1e2dbf518731447c95a3 100644
--- a/content/shell/renderer/test_runner/MockColorChooser.cpp
+++ b/content/shell/renderer/test_runner/MockColorChooser.cpp
@@ -7,11 +7,11 @@
 #include "content/shell/renderer/test_runner/WebTestDelegate.h"
 #include "content/shell/renderer/test_runner/WebTestProxy.h"
 
+using namespace WebTestRunner;
 using namespace blink;
-using namespace content;
 using namespace std;
 
-namespace WebTestRunner {
+namespace content {
 
 namespace {
 class HostMethodTask : public WebMethodTask<MockColorChooser> {
@@ -56,4 +56,4 @@ void MockColorChooser::invokeDidEndChooser()
     m_client->didEndChooser();
 }
 
-}
+}  // namespace content