tp: add support for shell on Android

Change-Id: I2ee77c8501b4bfe4b840de0d38c776ef273cc2b8
diff --git a/tools/diff_test_trace_processor.py b/tools/diff_test_trace_processor.py
index c9298b5..49034be 100755
--- a/tools/diff_test_trace_processor.py
+++ b/tools/diff_test_trace_processor.py
@@ -341,9 +341,16 @@
     trace_descriptor_path = args.trace_descriptor
   else:
     out_path = os.path.dirname(args.trace_processor)
-    trace_protos_path = os.path.join(out_path, 'gen', 'protos', 'perfetto',
-                                     'trace')
-    trace_descriptor_path = os.path.join(trace_protos_path, 'trace.descriptor')
+
+    def find_trace_descriptor(parent):
+      trace_protos_path = os.path.join(parent, 'gen', 'protos', 'perfetto',
+                                       'trace')
+      return os.path.join(trace_protos_path, 'trace.descriptor')
+
+    trace_descriptor_path = find_trace_descriptor(out_path)
+    if not os.path.exists(trace_descriptor_path):
+      trace_descriptor_path = find_trace_descriptor(
+          os.path.join(out_path, 'gcc_like_host'))
 
   if args.metrics_descriptor:
     metrics_descriptor_path = args.metrics_descriptor