Receive intent callbacks without launching intents

ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java

Index: ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java
diff --git a/ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java b/ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java
index ddc2ddd462a8639f31e878f2510b78c145363dfa..2c5948ed3ab802f5754452b5be43cf93d37e01e6 100644
--- a/ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java
+++ b/ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java
@@ -130,6 +130,17 @@ public class ActivityWindowAndroid
     }
 
     @Override
+    public int addIntentCallback(IntentCallback callback, Integer errorId) {

[Ted C, 2016/04/19 21:30:24]

I'd be tempted to do something more like this:

public int showCancelableIntent(
        Callback<Integer> intentTrigger, IntentCallback callback, Integer
errorId) {
    Activity activity = getActivity().get();
    if (activity == null) return START_INTENT_FAILURE;

    int requestCode = generateNextRequestCode();

    intentTrigger.onResult(requestCocde);

    storeCallbackData(requestCode, callback, errorId);
    return requestCode;
}

A bit more verbose but it keeps this in line w/ the above calls.  I don't feel
too strongly though as they both aren't exactly ideal.

+        Activity activity = getActivity().get();
+        if (activity == null) return START_INTENT_FAILURE;
+
+        int requestCode = generateNextRequestCode();
+
+        storeCallbackData(requestCode, callback, errorId);
+        return requestCode;
+    }
+
+    @Override
     public void cancelIntent(int requestCode) {
         Activity activity = getActivity().get();
         if (activity == null) return;