Add initial support for runtime permissions in android M.

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 c83a0cac60cc7f05dac183db393efd6c1663fb36..6e6e308b24a757aced7c88cdc6779df1a682cd39 100644
--- a/ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java
+++ b/ui/android/java/src/org/chromium/ui/base/ActivityWindowAndroid.java
@@ -9,6 +9,8 @@ import android.app.PendingIntent;
 import android.content.ActivityNotFoundException;
 import android.content.Intent;
 import android.content.IntentSender.SendIntentException;
+import android.os.Handler;
+import android.util.SparseArray;
 import android.view.View;
 
 import org.chromium.base.ActivityState;
@@ -16,6 +18,8 @@ import org.chromium.base.ApplicationStatus;
 import org.chromium.ui.UiUtils;
 
 import java.lang.ref.WeakReference;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
 
 /**
  * The class provides the WindowAndroid's implementation which requires
@@ -31,6 +35,12 @@ public class ActivityWindowAndroid
     private static final String TAG = "ActivityWindowAndroid";
 
     private final WeakReference<Activity> mActivityRef;
+    private final Handler mHandler;
+    private final SparseArray<PermissionCallback> mOutstandingPermissionRequests;
+    private final Runnable mClearPermissionRequestsTask;
+
+    private Method mRequestPermissionsMethod;
+
     private int mNextRequestCode = 0;
 
     /**
@@ -51,6 +61,17 @@ public class ActivityWindowAndroid
     public ActivityWindowAndroid(Activity activity, boolean listenToActivityState) {
         super(activity.getApplicationContext());
         mActivityRef = new WeakReference<Activity>(activity);
+        mHandler = new Handler();
+        mOutstandingPermissionRequests = new SparseArray<PermissionCallback>();
+        mClearPermissionRequestsTask = new Runnable() {
+            @Override
+            public void run() {
+                for (int i = 0; i < mOutstandingPermissionRequests.size(); i++) {
+                    mOutstandingPermissionRequests.valueAt(i).onRequestPermissionAborted();
+                }
+                mOutstandingPermissionRequests.clear();
+            }
+        };
         if (listenToActivityState) {
             ApplicationStatus.registerStateListenerForActivity(this, activity);
         }
@@ -113,7 +134,13 @@ public class ActivityWindowAndroid
         activity.finishActivity(requestCode);
     }
 
-    @Override
+    /**
+     * Responds to the intent result if the intent was created by the native window.
+     * @param requestCode Request code of the requested intent.
+     * @param resultCode Result code of the requested intent.
+     * @param data The data returned by the intent.
+     * @return Boolean value of whether the intent was started by the native window.
+     */
     public boolean onActivityResult(int requestCode, int resultCode, Intent data) {
         IntentCallback callback = mOutstandingIntents.get(requestCode);
         mOutstandingIntents.delete(requestCode);
@@ -133,6 +160,53 @@ public class ActivityWindowAndroid
     }
 
     @Override
+    public void requestPermissions(String[] permissions, PermissionCallback callback) {
+        mHandler.removeCallbacks(mClearPermissionRequestsTask);
+
+        // TODO(tedchoc): Remove the reflection aspect of this once a public M SDK is available.
+        Activity activity = mActivityRef.get();
+        if (activity == null) return;
+
+        if (mRequestPermissionsMethod == null) {
+            try {
+                mRequestPermissionsMethod = Activity.class.getMethod(
+                        "requestPermissions", String[].class, int.class);
+            } catch (NoSuchMethodException e) {
+                return;
+            }
+        }
+
+        int requestCode = generateNextRequestCode();
+        mOutstandingPermissionRequests.put(requestCode, callback);
+
+        try {
+            mRequestPermissionsMethod.invoke(activity, permissions, requestCode);
+        } catch (IllegalAccessException e) {
+            mOutstandingPermissionRequests.delete(requestCode);
+        } catch (IllegalArgumentException e) {
+            mOutstandingPermissionRequests.delete(requestCode);
+        } catch (InvocationTargetException e) {
+            mOutstandingPermissionRequests.delete(requestCode);
+        }
+    }
+
+    /**
+     * Responds to a pending permission result.
+     * @param requestCode The unique code for the permission request.
+     * @param permissions The list of permissions in the result.
+     * @param grantResults Whether the permissions were granted.
+     * @return Whether the permission request corresponding to a pending permission request.
+     */
+    public boolean onRequestPermissionsResult(int requestCode, String[] permissions,
+            int[] grantResults) {
+        PermissionCallback callback = mOutstandingPermissionRequests.get(requestCode);
+        mOutstandingPermissionRequests.delete(requestCode);
+        if (callback == null) return false;
+        callback.onRequestPermissionsResult(permissions, grantResults);
+        return true;
+    }
+
+    @Override
     public WeakReference<Activity> getActivity() {
         // Return a new WeakReference to prevent clients from releasing our internal WeakReference.
         return new WeakReference<Activity>(mActivityRef.get());
@@ -144,6 +218,11 @@ public class ActivityWindowAndroid
             onActivityPaused();
         } else if (newState == ActivityState.RESUMED) {
             onActivityResumed();
+
+            // Work around an issue where we do not always get an onRequestPermissionsResult
+            // callback if the user hits the back button in the permission dialog instead
+            // of taking an action.
+            mHandler.post(mClearPermissionRequestsTask);
         }
     }