android_webview: Build against NDK prebuilts, not system libraries.

android_webview/libwebviewchromium.gypi

Index: android_webview/libwebviewchromium.gypi
diff --git a/android_webview/libwebviewchromium.gypi b/android_webview/libwebviewchromium.gypi
index 0e605f0bc63913061f016d4b2ff6ee573dad19af..3d87388de6ba10a083579b3b16295a2087f810a9 100644
--- a/android_webview/libwebviewchromium.gypi
+++ b/android_webview/libwebviewchromium.gypi
@@ -49,16 +49,6 @@
         '-Wl,--fatal-warnings',
       ],
     }],
-    ['android_webview_build==1 and use_system_stlport==1', {
-      # ICU requires RTTI, which is not present in the system's stlport, so
-      # we have to include gabi++. We can't include it in icu.gyp because
-      # link_settings cannot be used inside target_conditions. This will be
-      # removed once we stop using the system stlport.
-      # http://crbug.com/409851
-      'libraries': [
-        '-lgabi++',
-      ],
-    }],
   ],
   'sources': [
     'lib/main/webview_entry_point.cc',