Add missing (and remove superfluous) 'explicit' from constructors.

webkit/tools/test_shell/test_navigation_controller.h

Index: webkit/tools/test_shell/test_navigation_controller.h
diff --git a/webkit/tools/test_shell/test_navigation_controller.h b/webkit/tools/test_shell/test_navigation_controller.h
index 17de056b95b0a684f51ce82ef91bb0a0742a23b7..e2ce67e7c355f0084010badf77e5646fb2502d8f 100644
--- a/webkit/tools/test_shell/test_navigation_controller.h
+++ b/webkit/tools/test_shell/test_navigation_controller.h
@@ -21,7 +21,7 @@ class TestShell;
 // Associated with browser-initated navigations to hold tracking data.
 class TestShellExtraData : public WebKit::WebDataSource::ExtraData {
  public:
-  TestShellExtraData(int32 pending_page_id)
+  explicit TestShellExtraData(int32 pending_page_id)
       : pending_page_id(pending_page_id),
         request_committed(false) {
   }
@@ -80,7 +80,7 @@ class TestNavigationEntry {
 // version as possible.
 class TestNavigationController {
  public:
-  TestNavigationController(TestShell* shell);
+  explicit TestNavigationController(TestShell* shell);
   ~TestNavigationController();
 
   void Reset();