Have mojo_shell run in its custom thread on android.

mojo/shell/android/apk/src/org/chromium/mojo_shell_apk/MojoMain.java

Index: mojo/shell/android/apk/src/org/chromium/mojo_shell_apk/MojoMain.java
diff --git a/mojo/shell/android/apk/src/org/chromium/mojo_shell_apk/MojoMain.java b/mojo/shell/android/apk/src/org/chromium/mojo_shell_apk/MojoMain.java
index 55fa0becaf0dba08af19c06b20ff78ed7dba9691..7a27003feadcaf0fb2ec59a38265378c4cba0e29 100644
--- a/mojo/shell/android/apk/src/org/chromium/mojo_shell_apk/MojoMain.java
+++ b/mojo/shell/android/apk/src/org/chromium/mojo_shell_apk/MojoMain.java
@@ -31,13 +31,13 @@ public class MojoMain {
     /**
      * Starts the specified application in the specified context.
      **/
-    public static void start(Context context, String appUrl) {
-        nativeStart(context, appUrl);
+    public static void start(final String appUrl) {
+        nativeStart(appUrl);
     }
 
     /**
      * Initializes the native system. This API should be called only once per process.
      **/
     private static native void nativeInit(Context context);
-    private static native void nativeStart(Context context, String appUrl);
+    private static native void nativeStart(String appUrl);
 };