Define a Java-side global application context.

mojo/runner/android/android_handler.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/runner/android/android_handler.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
@@ skipping 33 matching lines @@
   // needed.
   // TODO(vtl): We'd use a ScopedNativeLibrary, but it doesn't have .get()!
   base::NativeLibrary app_library = LoadNativeApplication(app_path);
   if (!app_library)
     return;
 
   // Set the application context if needed. Most applications will need to
   // 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>&);
   InitApplicationContextFn init_application_context =
       reinterpret_cast<InitApplicationContextFn>(
           base::GetFunctionPointerFromNativeLibrary(
               app_library, init_application_context_name));
   if (init_application_context) {
     base::android::ScopedJavaLocalRef<jobject> scoped_context(env, j_context);
     init_application_context(scoped_context);
@@ skipping 107 matching lines @@
   connection->AddService(&content_handler_factory_);
   return true;
 }
 
 bool RegisterAndroidHandlerJni(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace runner
 }  // namespace mojo