Define a Java-side global application context.

mojo/runner/android/android_handler.cc

Index: mojo/runner/android/android_handler.cc
diff --git a/mojo/runner/android/android_handler.cc b/mojo/runner/android/android_handler.cc
index 354720a4968621bd71506983ee8b0cab1d7e936c..7a7579b6030eac1179a8bdeb59f1d94c17bea152 100644
--- a/mojo/runner/android/android_handler.cc
+++ b/mojo/runner/android/android_handler.cc
@@ -51,6 +51,7 @@ void RunAndroidApplication(JNIEnv* env,
   // access the Android ApplicationContext in which they are run. If the
   // application library exports the InitApplicationContext function, we will
   // set it there.
+  // TODO: what to do about this?

[Torne, 2015/11/06 16:43:19]

Mojo folks: is it reasonable to remove this mechanism and instead handle the
application context purely on the Java side? That's what would best match the
rest of my change.

Also, is it actually necessary to set the application context in the mojo shell
and also in the application being loaded? I'm not clear on what's going on here
:)

[qsr, 2015/11/13 14:36:06]

 Unfortunately, I don't think you can do this.
The code here (in interaction with org.chromium.mojo.shell.AndroidHandler) is
loading a dex file from the web, creating a new classloader that only depends on
the system class loader and not the app class loader. So, in particular, this
code doesn't have access to ApplicationStatus, or anything in base_java. This
mechanism is the way we inject the context to this new class loader.

   const char* init_application_context_name = "InitApplicationContext";
   typedef void (*InitApplicationContextFn)(
       const base::android::JavaRef<jobject>&);