This patch is the rest of the lint cleanup minus the other open issue.

chrome/common/notification_source.h

Index: chrome/common/notification_source.h
diff --git a/chrome/common/notification_source.h b/chrome/common/notification_source.h
index fb371241fdbdcdeaf59f1cbe8d3e8e87d0821355..5cdedb188e597ff6f1cb85c56857499590484a18 100644
--- a/chrome/common/notification_source.h
+++ b/chrome/common/notification_source.h
@@ -31,7 +31,7 @@ class NotificationSource {
   }
 
  protected:
-  NotificationSource(const void* ptr) : ptr_(ptr) {}
+  explicit NotificationSource(const void* ptr) : ptr_(ptr) {}
 
   // Declaring this const allows Source<T> to be used with both T = Foo and
   // T = const Foo.
@@ -41,9 +41,9 @@ class NotificationSource {
 template <class T>
 class Source : public NotificationSource {
  public:
-  Source(T* ptr) : NotificationSource(ptr) {}
+  explicit Source(T* ptr) : NotificationSource(ptr) {}
 
-  Source(const NotificationSource& other)
+  explicit Source(const NotificationSource& other)
     : NotificationSource(other) {}
 
   T* operator->() const { return ptr(); }