metrics: Refactor app_startup to be time_period

Refactor instances where structs/files were named "app_startup" to be
"time_period", so that these instances can be re-used for other metrics
that require time_periods that are unrelated to app_startups.

Test: tools/diff_test_trace_processor.py out/linux/trace_processor_shell --name-filter '.*wattson.*'
Bug: 352627297
Change-Id: I3cbac9157d2947b236f39b1c5848431b4ba8b74f
Signed-off-by: Samuel Wu <wusamuel@google.com>
diff --git a/Android.bp b/Android.bp
index 1144fdf..cfc6fc6 100644
--- a/Android.bp
+++ b/Android.bp
@@ -5304,7 +5304,7 @@
         "protos/perfetto/metrics/android/thread_time_in_state_metric.proto",
         "protos/perfetto/metrics/android/trace_quality.proto",
         "protos/perfetto/metrics/android/unsymbolized_frames.proto",
-        "protos/perfetto/metrics/android/wattson_app_startup.proto",
+        "protos/perfetto/metrics/android/wattson_in_time_period.proto",
         "protos/perfetto/metrics/chrome/all_chrome_metrics.proto",
         "protos/perfetto/metrics/chrome/args_class_names.proto",
         "protos/perfetto/metrics/chrome/dropped_frames.proto",
@@ -5398,7 +5398,7 @@
         "protos/perfetto/metrics/android/thread_time_in_state_metric.proto",
         "protos/perfetto/metrics/android/trace_quality.proto",
         "protos/perfetto/metrics/android/unsymbolized_frames.proto",
-        "protos/perfetto/metrics/android/wattson_app_startup.proto",
+        "protos/perfetto/metrics/android/wattson_in_time_period.proto",
         "protos/perfetto/metrics/metrics.proto",
     ],
     tools: [
@@ -5476,7 +5476,7 @@
         "protos/perfetto/metrics/android/thread_time_in_state_metric.proto",
         "protos/perfetto/metrics/android/trace_quality.proto",
         "protos/perfetto/metrics/android/unsymbolized_frames.proto",
-        "protos/perfetto/metrics/android/wattson_app_startup.proto",
+        "protos/perfetto/metrics/android/wattson_in_time_period.proto",
         "protos/perfetto/metrics/metrics.proto",
         "protos/perfetto/metrics/webview/all_webview_metrics.proto",
         "protos/perfetto/metrics/webview/webview_jank_approximation.proto",