[WebAPK] Unblock Chrome APK optimization on O+

These flags are potentially preventing Chrome from being optimized on
O+ devices. Having spoke with agrieve@ there is no easy way to ensure
that these flags are the culprit with monochrome. However, if we move
away from monochrome this will at least ensure that WebAPKs aren't the
blocker of optimization.

I've tested this on L, N and O devices and confirmed there don't
appear to be any negative effects or crashes resulting from their
removal.

Notifications were tested using:
https://tests.peter.sh/notification-generator/
as well as the bound and unbound WebAPK targets.

Change-Id: I4e93db09aec3271493b29bfd310d1df8f27cb4d7
Reviewed-on: https://chromium-review.googlesource.com/1127150Reviewed-by: Xi Han <hanxi@chromium.org>
Reviewed-by: agrieve <agrieve@chromium.org>
Commit-Queue: Calder Kitagawa <ckitagawa@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577529}

chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/WebApkUtils.java

@@ -71,7 +71,7 @@ public class WebApkUtils {
         try {
             String hostPackage = getHostBrowserPackageName(context);
             return context.getApplicationContext().createPackageContext(
-                    hostPackage, Context.CONTEXT_IGNORE_SECURITY | Context.CONTEXT_INCLUDE_CODE);
+                    hostPackage, 0);
         } catch (NameNotFoundException e) {
             e.printStackTrace();
         }