MB: Add WebRTC codesearch builder config

Identical to Chromium's code search builders with the exception
that is_component_build=true is not set, as it doesn't have any
effect on WebRTC builds.

Adding strip_absolute_paths_from_debug_symbols=true to the
minimal_symbols mixin as recently changed in Chromium.

BUG=chromium:699463
NOTRY=True

Review-Url: https://codereview.webrtc.org/2892723002
Cr-Commit-Position: refs/heads/master@{#18192}
diff --git a/tools_webrtc/mb/mb_config.pyl b/tools_webrtc/mb/mb_config.pyl
index da91186..c937e90 100644
--- a/tools_webrtc/mb/mb_config.pyl
+++ b/tools_webrtc/mb/mb_config.pyl
@@ -107,6 +107,10 @@
       'Win64 Debug (Win8)': 'debug_bot_x64',
       'Win64 Debug (Win10)': 'debug_bot_x64',
     },
+    'chromium.infra.codesearch': {
+      'codesearch-gen-webrtc-android': 'android_debug_static_bot_arm',
+      'codesearch-gen-webrtc-linux': 'codesearch_gen_linux_bot',
+    },
     'tryserver.webrtc': {
       # iOS
       'ios_dbg': 'ios',
@@ -225,6 +229,9 @@
     'debug_bot_x64': [
       'gn', 'openh264_debug_bot', 'x64'
     ],
+    'codesearch_gen_linux_bot': [
+      'gn', 'openh264_debug_bot', 'minimal_symbols'
+    ],
     'release_bot_x64': [
       'gn', 'openh264_release_bot', 'x64'
     ],
@@ -391,17 +398,13 @@
     },
 
     'minimal_symbols': {
-      'gn_args': 'symbol_level=1',
+      'gn_args': 'symbol_level=1 strip_absolute_paths_from_debug_symbols=true',
     },
 
     'mipsel': {
       'gn_args': 'target_cpu="mipsel"',
     },
 
-    'minimal_symbols': {
-      'gn_args': 'symbol_level=1',
-    },
-
     'msan': {
       'gn_args': ('is_msan=true msan_track_origins=2 '
                   'use_prebuilt_instrumented_libraries=true'),