*** note
Note: this requires either a userdebug or eng Android build (you can
check with adb shell getprop ro.build.type). Flags cannot be enabled on
production builds of Android.
WebView reads flags from a specific file during startup. To enable flags, write to the file with:
$ # Overwrites all flags (and prints the new flag state):
$ build/android/adb_system_webview_command_line \
--show-composited-layer-borders \
--log-net-log=foo.json # Supports multiple flags
$ # Simply prints the existing flag state:
$ build/android/adb_system_webview_command_line
$ # Passing empty string clears all flags:
$ build/android/adb_system_webview_command_line ""Or, you can use the adb in your $PATH like so:
$ FLAG_FILE=/data/local/tmp/webview-command-line
$ adb shell "echo '_ --show-composited-layer-borders' > ${FLAG_FILE}"
$ # The first token is ignored. We use '_' as a convenient placeholder, but any
$ # token is acceptable.*** note Note: either set of commands will overwrite existing flags.
WebView supports the same --enable-features=feature1,feature2 and
--disable-features=feature3,feature4 syntax as the rest of Chromium. You can
use these like any other flag. Please consult
base/feature_list.h
for details.
WebView supports any flags supported in any layer we depend on (ex. content). Some interesting flags and Features:
--show-composited-layer-borders--enable-features=NetworkService,NetworkServiceInProcess--log-net-log=<filename.json>
WebView also defines its own flags and Features:
- AwSwitches.java (and its native counterpart)
- AwFeatureList.java (and its native counterpart)
See CommandLineUtil.java.