Deprecate get_browser_timing_footer API (#999)

* Add nonce to CSP in browser agent

* Adjust nonce position

* Add testing for browser timing nonces

* Deprecated browser timing footer APIs.

* Full rip out of browser timing footer

* Remove cross agent tests for RUM footer (per repo)

* Update cat_map tests

* Adjust browser header generation timing accuracy

* Fix browser tests

* Linting

* Apply suggestions from code review

---------

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Author: TimPansino

newrelic/api/asgi_application.py

@@ -157,16 +157,9 @@ async def send_inject_browser_agent(self, message):
 
             # if there's a valid body string, attempt to insert the HTML
             if verify_body_exists(self.body):
-                header = self.transaction.browser_timing_header()
-                if not header:
-                    # If there's no header, abort browser monitoring injection
-                    await self.send_buffered()
-                    return
-
-                footer = self.transaction.browser_timing_footer()
-                browser_agent_data = six.b(header) + six.b(footer)
-
-                body = insert_html_snippet(self.body, lambda: browser_agent_data, self.search_maximum)
+                body = insert_html_snippet(
+                    self.body, lambda: six.b(self.transaction.browser_timing_header()), self.search_maximum
+                )
 
                 # If we have inserted the browser agent
                 if len(body) != len(self.body):

newrelic/api/transaction.py

@@ -309,7 +309,7 @@ def __init__(self, application, enabled=None, source=None):
         self.synthetics_job_id = None
         self.synthetics_monitor_id = None
         self.synthetics_header = None
-        
+
         # Synthetics Info Header
         self.synthetics_type = None
         self.synthetics_initiator = None
@@ -1912,9 +1912,10 @@ def get_browser_timing_header(nonce=None):
 
 
 def get_browser_timing_footer(nonce=None):
-    transaction = current_transaction()
-    if transaction and hasattr(transaction, "browser_timing_footer"):
-        return transaction.browser_timing_footer(nonce)
+    warnings.warn(
+        "The get_browser_timing_footer function is deprecated. Please migrate to only using the get_browser_timing_header API instead.",
+        DeprecationWarning,
+    )
     return ""