[gn] Switch custom snapsot bot to gn

BUG=chromium:474921
NOTRY=true

Review-Url: https://codereview.chromium.org/2113583002
Cr-Commit-Position: refs/heads/master@{#37431}

BUILD.gn

@@ -28,6 +28,9 @@ declare_args() {
   # Enable compiler warnings when using V8_DEPRECATE_SOON apis.
   v8_imminent_deprecation_warnings = false
 
+  # Embeds the given script into the snapshot.
+  v8_embed_script = ""
+
   # Sets -dENABLE_DISASSEMBLER.
   v8_enable_disassembler = false
 
@@ -588,6 +591,8 @@ action("run_mksnapshot") {
 
   script = "tools/run.py"
 
+  sources = []
+
   outputs = [
     "$target_gen_dir/snapshot.cc",
   ]
@@ -614,6 +619,11 @@ action("run_mksnapshot") {
       rebase_path("$root_out_dir/snapshot_blob.bin", root_build_dir),
     ]
   }
+
+  if (v8_embed_script != "") {
+    sources += [ v8_embed_script ]
+    args += [ rebase_path(v8_embed_script, root_build_dir) ]
+  }
 }
 
 ###############################################################################

infra/mb/mb_config.pyl

@@ -27,7 +27,7 @@
       # Linux64.
       'V8 Linux64 - builder': 'gn_release_x64',
       'V8 Linux64 - debug builder': 'gn_debug_x64_valgrind',
-      'V8 Linux64 - custom snapshot - debug builder': 'gyp_debug_x64_custom',
+      'V8 Linux64 - custom snapshot - debug builder': 'gn_debug_x64_custom',
       'V8 Linux64 - internal snapshot': 'gn_release_x64_internal',
       # Windows.
       'V8 Win32 - builder': 'gyp_release_x86_minimal_symbols',
@@ -186,6 +186,8 @@
       'gn', 'release_trybot', 'x64', 'swarming'],
 
     # GN debug configs for x64.
+    'gn_debug_x64_custom': [
+      'gn', 'debug_bot', 'x64', 'swarming', 'v8_snapshot_custom'],
     'gn_debug_x64_trybot': [
       'gn', 'debug_trybot', 'x64', 'swarming'],
     'gn_debug_x64_valgrind': [
@@ -216,8 +218,6 @@
       'gyp', 'debug_bot', 'x64', 'swarming'],
     'gyp_debug_x64_asan_edge': [
       'gyp', 'debug_bot', 'x64', 'asan', 'lsan', 'edge'],
-    'gyp_debug_x64_custom': [
-      'gyp', 'debug_bot', 'x64', 'swarming', 'v8_snapshot_custom'],
     'gyp_debug_x64_minimal_symbols': [
       'gyp', 'debug_bot', 'x64', 'minimal_symbols', 'swarming'],
 
@@ -589,8 +589,10 @@
     },
 
     'v8_snapshot_custom': {
-      # TODO(machenbach): Add this to gn.
-      # Path needs to be relative to src/v8.gyp.
+      # GN path is relative to project root.
+      'gn_args': 'v8_embed_script=test/mjsunit/mjsunit.js',
+
+      # Gyp path is relative to src/v8.gyp.
       'gyp_defines': 'embed_script=../test/mjsunit/mjsunit.js',
     },