Check that Diagnostic subclasses are registered in presubmit.

tracing/tracing_project.py

Index: tracing/tracing_project.py
diff --git a/tracing/tracing_project.py b/tracing/tracing_project.py
index 38b5225895451ec09ac84da569f9f2be4dc45d79..3bdcb4e4d2e026fa249e78bafe55f5e06ad63cd2 100644
--- a/tracing/tracing_project.py
+++ b/tracing/tracing_project.py
@@ -87,6 +87,7 @@ class TracingProject(object):
   mre_path = os.path.join(tracing_src_path, 'mre')
 
   metrics_path = os.path.join(tracing_src_path, 'metrics')
+  diagnostics_path = os.path.join(tracing_src_path, 'value', 'diagnostics')
 
   value_ui_path = os.path.join(tracing_src_path, 'value', 'ui')
   metrics_ui_path = os.path.join(tracing_src_path, 'metrics', 'ui')
@@ -151,6 +152,16 @@ class TracingProject(object):
     return [os.path.relpath(x, self.tracing_root_path)
             for x in all_metrics_module_filenames]
 
+  def FindAllDiagnosticsModuleRelPaths(self):
+    all_filenames = _FindAllFilesRecursive([self.tracing_src_path])
+    all_diagnostics_module_filenames = []
+    for x in all_filenames:
+      if x.startswith(self.diagnostics_path) and not _IsFilenameATest(x):
+        all_diagnostics_module_filenames.append(x)
+    all_diagnostics_module_filenames.sort()
+    return [os.path.relpath(x, self.tracing_root_path)
+            for x in all_diagnostics_module_filenames]
+
   def FindAllD8TestModuleRelPaths(self):
     return self.FindAllTestModuleRelPaths(pred=self.IsD8CompatibleFile)