Disable webrtc for Android system build

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index ef268a88684dba18c798f90fd7a4f26f52c6c275..e865e690c8d0c44cc8dc12b0a75b90869762305e 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -490,11 +490,21 @@
           'enable_language_detection%': 0,
           'enable_printing%': 0,
           'enable_themes%': 0,
-          'enable_webrtc%': 1,
           'proprietary_codecs%': 1,
           'remoting%': 0,
         }],
 
+        ['OS=="android" and android_build_type==0', {
+          'enable_webrtc%': 1,
+        }],
+
+        # Disable WebRTC for building WebView as part of Android system.
+        # TODO(boliu): Decide if we want WebRTC, and if so, also merge
+        # the necessary third_party repositories.
+        ['OS=="android" and android_build_type==1', {
+          'enable_webrtc%': 0,
+        }],
+
         ['OS=="ios"', {
           'configuration_policy%': 0,
           'disable_ftp_support%': 1,