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

chrome/browser/autofill/autofill_external_delegate_unittest.cc

Index: chrome/browser/autofill/autofill_external_delegate_unittest.cc
diff --git a/chrome/browser/autofill/autofill_external_delegate_unittest.cc b/chrome/browser/autofill/autofill_external_delegate_unittest.cc
index 5535debe523387910996244e871cffb3d1e6c910..eb04e9c6b3f94f616dfbbbd2848ef24bbe8d033b 100644
--- a/chrome/browser/autofill/autofill_external_delegate_unittest.cc
+++ b/chrome/browser/autofill/autofill_external_delegate_unittest.cc
@@ -55,8 +55,8 @@ class MockAutofillExternalDelegate :
 
 class MockAutofillManager : public AutofillManager {
  public:
-  explicit MockAutofillManager(content::WebContents* web_contents,
-                               autofill::AutofillManagerDelegate* delegate)
+  MockAutofillManager(content::WebContents* web_contents,
+                      autofill::AutofillManagerDelegate* delegate)
       // Force to use the constructor designated for unit test, but we don't
       // really need personal_data in this test so we pass a NULL pointer.
       : AutofillManager(web_contents, delegate, NULL) {