added new error ID and exposed it to the Install object in javascript. This is part of fixing bug #18704. r=dbragg

xpinstall/src/nsInstall.h

@@ -147,6 +147,7 @@ class nsInstall
             SOURCE_DOES_NOT_EXIST       = -232,
             SOURCE_IS_DIRECTORY         = -233,
             SOURCE_IS_FILE              = -234,
+            INSUFFICIENT_DISK_SPACE     = -235,
             
             OUT_OF_MEMORY               = -299,
 

xpinstall/src/nsJSInstall.cpp

@@ -2688,6 +2688,7 @@ static JSConstDoubleSpec install_constants[] =
     { nsInstall::SOURCE_DOES_NOT_EXIST,      "SOURCE_DOES_NOT_EXIST"        },
     { nsInstall::SOURCE_IS_DIRECTORY,        "SOURCE_IS_DIRECTORY"          },
     { nsInstall::SOURCE_IS_FILE,             "SOURCE_IS_FILE"               },
+    { nsInstall::INSUFFICIENT_DISK_SPACE,    "INSUFFICIENT_DISK_SPACE"      },
 
     { nsInstall::GESTALT_UNKNOWN_ERR,        "GESTALT_UNKNOWN_ERR"          },
     { nsInstall::GESTALT_INVALID_ARGUMENT,   "GESTALT_INVALID_ARGUMENT"     },