scc and I decided that the explicit keyword was not necessary for the constructor.

It never hurts you to make an nsCOMPtr.  MJ

xpcom/base/nsCOMPtr.h

@@ -417,7 +417,6 @@ class nsCOMPtr
     public:
       typedef T element_type;
 
-      explicit
       nsCOMPtr( nsISupports* aRawPtr = 0 )
       		: mRawPtr(0),
       			mIsAwaitingAddRef(0)

xpcom/glue/nsCOMPtr.h

@@ -417,7 +417,6 @@ class nsCOMPtr
     public:
       typedef T element_type;
 
-      explicit
       nsCOMPtr( nsISupports* aRawPtr = 0 )
       		: mRawPtr(0),
       			mIsAwaitingAddRef(0)

xpcom/public/nsCOMPtr.h

@@ -417,7 +417,6 @@ class nsCOMPtr
     public:
       typedef T element_type;
 
-      explicit
       nsCOMPtr( nsISupports* aRawPtr = 0 )
       		: mRawPtr(0),
       			mIsAwaitingAddRef(0)

xpcom/public/nsISupports.h

@@ -76,6 +76,7 @@ typedef PRUint32 nsrefcnt;
  */
 class nsISupports {
 public:
+  static const nsIID& IID() { static nsIID iid = NS_ISUPPORTS_IID; return iid; }
   /**
    * @name Methods
    */