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

content/test/layout_browsertest.h

Index: content/test/layout_browsertest.h
diff --git a/content/test/layout_browsertest.h b/content/test/layout_browsertest.h
index 583bac2a401aed91ca2e211d523da8cc3ed31482..2029631daf7ec54ca83c25dbead2e2b1d21bd62a 100644
--- a/content/test/layout_browsertest.h
+++ b/content/test/layout_browsertest.h
@@ -14,8 +14,8 @@ class WebKitTestController;
 
 class InProcessBrowserLayoutTest : public ContentBrowserTest {
  public:
-  explicit InProcessBrowserLayoutTest(const FilePath& test_parent_dir,
-                                      const FilePath& test_case_dir);
+  InProcessBrowserLayoutTest(const FilePath& test_parent_dir,
+                             const FilePath& test_case_dir);
   // Used when running HTTP layout tests. Starts the server in the constructor
   // and keeps it running through the lifetime of this test. This is done to
   // avoid flakiness in restarting the server while the port is still in use.