Adding android-webview platform to sizes.py script.
Adding android-webview platform to sizes.py script.

This is to allow WebView binary (.so) to be monitored in the
perf dashboard.

BUG=251008

Review URL: https://chromiumcodereview.appspot.com/17071005

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@206874 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build