Remove `generate_py_runtime` from metrics protos

This change is applied manually in Chromium in order to make sure we can
safely remove this config option (it looks unused). If this CL doesn't
get rolled back, we'll update the export tool to skip
`generate_py_runtime` too.

Bug: b:467344756
Change-Id: Ia0f80d34dd4f36e461e33e10621271a9db160930
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7242963
Commit-Queue: Kamil Jarosz <kjarosz@google.com>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1558304}
diff --git a/third_party/metrics_proto/BUILD.gn b/third_party/metrics_proto/BUILD.gn
index 918aaae..cb150b7f 100644
--- a/third_party/metrics_proto/BUILD.gn
+++ b/third_party/metrics_proto/BUILD.gn
@@ -51,7 +51,6 @@
 proto_library("metrics_proto") {
   sources = _proto_files
   proto_in_dir = "."
-  generate_py_runtime = true
 }
 
 if (is_android) {
diff --git a/third_party/metrics_proto/README.chromium b/third_party/metrics_proto/README.chromium
index 44fed82..eab69aa00 100644
--- a/third_party/metrics_proto/README.chromium
+++ b/third_party/metrics_proto/README.chromium
@@ -19,4 +19,5 @@
 
 
 Local Modifications:
-Unchanged from the output of the export script.
+* Removed generate_py_runtime = true. This was done for testing purposes before
+  removing it from the export script.
diff --git a/third_party/omnibox_proto/BUILD.gn b/third_party/omnibox_proto/BUILD.gn
index c1b089e4..e1ea502 100644
--- a/third_party/omnibox_proto/BUILD.gn
+++ b/third_party/omnibox_proto/BUILD.gn
@@ -29,7 +29,6 @@
 proto_library("omnibox_proto") {
   sources = _proto_files
   proto_in_dir = "."
-  generate_py_runtime = true
 }
 
 if (is_android) {
diff --git a/third_party/omnibox_proto/README.chromium b/third_party/omnibox_proto/README.chromium
index 73f67e8..dcf71715 100644
--- a/third_party/omnibox_proto/README.chromium
+++ b/third_party/omnibox_proto/README.chromium
@@ -19,4 +19,5 @@
   --output=$CHROMIUM_SRC/third_party/omnibox_proto
 
 Local Modifications:
-Unchanged from the output of the export script.
+* Removed generate_py_runtime = true. This was done for testing purposes before
+  removing it from the export script.