Android: expose CommandLine java methods

No change to logic. This exposes CommandLine.hasSwitch() and
CommandLine.appendSwitch(). These are used all over the code base, and
I can't think of a good reason to mark them @VisibleForTesting.

I know Android WebView definitely needs to use these APIs, since we have
some Java-only processes which need to check and manipulate the
commandline state, as well as some browser-process code which needs to
check the CommandLine early in startup (before native initialization).

Bug: 1107950
Test: autoninja -C out/Default system_webview_apk
Change-Id: Id0293c7e59c3c437cfd4870732de86e342b182d7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2310833
Commit-Queue: Nate Fischer <ntfschr@chromium.org>
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Auto-Submit: Nate Fischer <ntfschr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#790574}

base/android/java/src/org/chromium/base/CommandLine.java

@@ -36,7 +36,6 @@ public abstract class CommandLine {
      *  Returns true if this command line contains the given switch.
      *  (Switch names ARE case-sensitive).
      */
-    @VisibleForTesting
     public abstract boolean hasSwitch(String switchString);
 
     /**
@@ -68,7 +67,6 @@ public abstract class CommandLine {
      * this action happens before the switch is needed.
      * @param switchString the switch to add.  It should NOT start with '--' !
      */
-    @VisibleForTesting
     public abstract void appendSwitch(String switchString);
 
     /**