Make ExtensionPrefs paths relative, re-enable 2 ExtensionsService unit_tests

chrome/test/data/extensions/good/Preferences

Index: chrome/test/data/extensions/good/Preferences
diff --git a/chrome/test/data/extensions/good/Preferences b/chrome/test/data/extensions/good/Preferences
new file mode 100755
index 0000000000000000000000000000000000000000..b0c00122a271da5c9e83426a858fc71078b56e5a
--- /dev/null
+++ b/chrome/test/data/extensions/good/Preferences
@@ -0,0 +1,21 @@
+{
+   "extensions": {
+      "settings": {
+         "behllobkkfkfnphdnhnkndlbkcpglgmj": {
+            "location": 1,
+            "path": "behllobkkfkfnphdnhnkndlbkcpglgmj/1.0.0.0",
+            "state": 1
+         },
+         "bjafgdebaacbbbecmhlhpofkepfkgcpa": {
+            "location": 1,
+            "path": "bjafgdebaacbbbecmhlhpofkepfkgcpa/1.0",
+            "state": 1
+         },
+         "hpiknbiabeeppbpihjehijgoemciehgk": {
+            "location": 1,
+            "path": "hpiknbiabeeppbpihjehijgoemciehgk/2",
+            "state": 1
+         }
+      }
+   }
+}