AMTL updates and changes to adapt for them to fix menu crashes (bug 5921, r=psychonic).

AMTL:
Removes isVoid from AString.
Fixes support inserting to Vector at length.

--HG--
extra : rebase_source : 02805fad60c2b759a0e2e91c081144854a8e0b54

public/amtl/am-vector.h

@@ -86,14 +86,22 @@ class Vector : public AllocPolicy
   }
 
   // Shift all elements including |at| up by one, and insert |item| at the
-  // given position. This is a linear-time operation.
+  // given position. If |at| is one greater than the last usable index,
+  // i.e. |at == length()|, then this is the same as append(). No other
+  // invalid indexes are allowed.
+  //
+  // This is a linear-time operation.
   bool insert(size_t at, const T &item) {
+    if (at == length())
+      return append(item);
     if (!moveUp(at))
       return false;
     new (&data_[at]) T(item);
     return true;
   }
   bool insert(size_t at, Moveable<T> item) {
+    if (at == length())
+      return append(item);
     if (!moveUp(at))
       return false;
     new (&data_[at]) T(item);
@@ -104,7 +112,7 @@ class Vector : public AllocPolicy
   // element. This is a linear-time operation.
   void remove(size_t at) {
     for (size_t i = at; i < length() - 1; i++)
-      data_[i] = T(Moveable<T>(data_[i + 1]));
+      data_[i] = Moveable<T>(data_[i + 1]);
     pop();
   }
 
@@ -178,11 +186,12 @@ class Vector : public AllocPolicy
   }
 
   bool moveUp(size_t at) {
+    assert(at < nitems_);
     if (!growIfNeeded(1))
       return false;
     nitems_++;
     for (size_t i = nitems_ - 1; i > at; i--)
-      data_[i] = T(Moveable<T>(data_[i - 1]));
+      data_[i] = Moveable<T>(data_[i - 1]);
     return true;
   }