Add skia reviews to my_activity

Also, sort all the gerrit instances by url for clarity.

Change-Id: I89aea98f75de33e8673c929fb07df3b686ea6c15
Reviewed-on: https://chromium-review.googlesource.com/1228659
Commit-Queue: enne <enne@chromium.org>
Reviewed-by: Marc-Antoine Ruel <maruel@chromium.org>
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>

my_activity.py

@@ -96,9 +96,7 @@ rietveld_instances = [
 
 gerrit_instances = [
   {
-    'url': 'chromium-review.googlesource.com',
-    'shorturl': 'crrev.com/c',
-    'short_url_protocol': 'https',
+    'url': 'android-review.googlesource.com',
   },
   {
     'url': 'chrome-internal-review.googlesource.com',
@@ -106,11 +104,16 @@ gerrit_instances = [
     'short_url_protocol': 'https',
   },
   {
-    'url': 'android-review.googlesource.com',
+    'url': 'chromium-review.googlesource.com',
+    'shorturl': 'crrev.com/c',
+    'short_url_protocol': 'https',
   },
   {
     'url': 'pdfium-review.googlesource.com',
   },
+  {
+    'url': 'skia-review.googlesource.com',
+  },
 ]
 
 monorail_projects = {