[Telemetry] Fix JavaScript interpolation in telemetry actions

telemetry/telemetry/internal/actions/mouse_click.py

Index: telemetry/telemetry/internal/actions/mouse_click.py
diff --git a/telemetry/telemetry/internal/actions/mouse_click.py b/telemetry/telemetry/internal/actions/mouse_click.py
index faeff8324557329fa6113839a6daf0ef35a241dc..3eec57bc37e46bdb040ab4093700854911e478a6 100644
--- a/telemetry/telemetry/internal/actions/mouse_click.py
+++ b/telemetry/telemetry/internal/actions/mouse_click.py
@@ -5,6 +5,7 @@
 from telemetry.internal.actions import page_action
 from telemetry.internal.actions import utils
 
+
 class MouseClickAction(page_action.PageAction):
   def __init__(self, selector=None):
     super(MouseClickAction, self).__init__()
@@ -14,12 +15,11 @@ class MouseClickAction(page_action.PageAction):
     """Load the mouse click JS code prior to running the action."""
     super(MouseClickAction, self).WillRunAction(tab)
     utils.InjectJavaScript(tab, 'mouse_click.js')
-    done_callback = 'function() { window.__mouseClickActionDone = true; }'
-    # TODO(catapult:#3028): Fix interpolation of JavaScript values.
     tab.ExecuteJavaScript("""
         window.__mouseClickActionDone = false;
-        window.__mouseClickAction = new __MouseClickAction(%s);"""
-        % (done_callback))
+        window.__mouseClickAction = new __MouseClickAction(function() {
+          window.__mouseClickActionDone = true;
+        });""")
 
   def RunAction(self, tab):
     code = '''