Add GN build for some chrome common, chrome net, and resources targets.

chrome/chrome_common.gypi

Index: chrome/chrome_common.gypi
diff --git a/chrome/chrome_common.gypi b/chrome/chrome_common.gypi
index 894a1be952bc5a979b106502de7ac4e872e3a985..3a0bd9c92660730259e10221ea7b4cb2546ec329 100644
--- a/chrome/chrome_common.gypi
+++ b/chrome/chrome_common.gypi
@@ -582,6 +582,7 @@
       ],
     },
     {
+      # GN version: //chrome/commoon/net:net
       'target_name': 'common_net',
       'type': 'static_library',
       'sources': [
@@ -664,6 +665,8 @@
       # Protobuf compiler / generator for the safebrowsing client
       # model proto and the client-side detection (csd) request
       # protocol buffer.
+
+      # GN version: //chrome/common/safe_browsing:proto
       'target_name': 'safe_browsing_proto',
       'type': 'static_library',
       'sources': [
@@ -679,6 +682,8 @@
     },
     {
       # Protobuf compiler / generator for UMA (User Metrics Analysis).
+
+      # GN version: //chrome/common/metrics/proto:proto
       'target_name': 'metrics_proto',
       'type': 'static_library',
       'sources': [