Add way to get native VR UI information from Java

chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java

Index: chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java
index 6112be34e224d80e8ea6d69d70165874a9ea9491..49379709b4e6da0a73009f945697ab00820bc5f7 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java
@@ -8,6 +8,7 @@ import android.annotation.SuppressLint;
 import android.graphics.Canvas;
 import android.graphics.Point;
 import android.os.StrictMode;
+import android.util.SparseArray;
 import android.view.MotionEvent;
 import android.view.Surface;
 import android.view.SurfaceHolder;
@@ -20,9 +21,13 @@ import android.widget.FrameLayout.LayoutParams;
 import com.google.vr.ndk.base.AndroidCompat;
 import com.google.vr.ndk.base.GvrLayout;
 
+import org.json.JSONException;
+import org.json.JSONObject;
+
 import org.chromium.base.CommandLine;
 import org.chromium.base.Log;
 import org.chromium.base.ThreadUtils;
+import org.chromium.base.VisibleForTesting;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
 import org.chromium.chrome.browser.ChromeActivity;
@@ -56,6 +61,9 @@ import org.chromium.ui.base.WindowAndroid;
 import org.chromium.ui.display.DisplayAndroid;
 import org.chromium.ui.display.VirtualDisplayAndroid;
 
+import java.util.HashMap;
+import java.util.Iterator;
+
 /**
  * This view extends from GvrLayout which wraps a GLSurfaceView that renders VR shell.
  */
@@ -97,6 +105,10 @@ public class VrShellImpl
     private Surface mSurface;
     private View mPresentationView;
 
+    private SparseArray<Runnable> mUiElementInfoReplyCallbacks;

[mthiesse, 2017/03/30 14:25:38]

Why do we need multiple callbacks at once? Seems unnecessarily complex. Can we
get away with having only one?

[bsheedy, 2017/03/30 21:05:14]

For testing, a single callback should be sufficient. Changed to support only one
callback now. I originally wrote this assuming we might need to get the native
UI info for non-testing purposes at some point, in which case multiple callbacks
might be necessary.

+    private HashMap<String, JSONObject> mUiElementInfoJson;
+    private int mCallbackCounter;
+
     // The tab that holds the main ContentViewCore.
     private Tab mTab;
     private NativePage mNativePage;
@@ -628,6 +640,55 @@ public class VrShellImpl
     @Override
     public void removeWindowAndroidChangedObserver(WindowAndroidChangedObserver observer) {}
 
+    @VisibleForTesting
+    public WebContents getUiContentsForTesting() {
+        return mUiContents;
+    }
+
+    // Lazily instantiate since we don't need it in most cases.
+    private SparseArray<Runnable> getUiElementInfoReplyCallbacksForTesting() {
+        if (mUiElementInfoReplyCallbacks == null) {
+            mUiElementInfoReplyCallbacks = new SparseArray<Runnable>();
+        }
+        return mUiElementInfoReplyCallbacks;
+    }
+
+    // Lazily instantiate since we don't need it in most cases.
+    @VisibleForTesting
+    public HashMap<String, JSONObject> getUiElementInfoJsonForTesting() {

[mthiesse, 2017/03/30 14:25:39]

Why expose this? Why not just create this object in
replyToUiElementInfoRequestForTesting and pass it through the callback?

[bsheedy, 2017/03/30 21:05:14]

Done.

+        if (mUiElementInfoJson == null) mUiElementInfoJson = new HashMap<String, JSONObject>();
+        return mUiElementInfoJson;
+    }
+
+    /**
+     * Sends an asynchronous request for native UI element information.
+     * @param elementIds The unique IDs of all the elements you want info on
+     * @param onReply The runnable that will be run when native replies
+     */
+    @VisibleForTesting
+    public void requestUiElementInfoFromNativeForTesting(String[] elementNames, Runnable onReply) {
+        getUiElementInfoReplyCallbacksForTesting().append(mCallbackCounter, onReply);
+        nativeRequestUiElementInfoForTesting(mNativeVrShell, elementNames, mCallbackCounter);
+        mCallbackCounter++;
+    }
+
+    @CalledByNative
+    public void replyToUiElementInfoRequestForTesting(String jsonString, int callbackId)
+            throws JSONException {
+        JSONObject reply = new JSONObject(jsonString);
+        HashMap<String, JSONObject> uiElementInfo = getUiElementInfoJsonForTesting();
+        for (Iterator<String> iter = reply.keys(); iter.hasNext();) {
+            String key = iter.next();
+            uiElementInfo.put(key, reply.optJSONObject(key));
+        }
+        SparseArray<Runnable> callbacks = getUiElementInfoReplyCallbacksForTesting();
+        Runnable callback = callbacks.get(callbackId);
+        if (callback != null) {
+            callback.run();
+        }
+        callbacks.remove(callbackId);
+    }
+
     private native long nativeInit(WebContents uiWebContents, long nativeContentWindowAndroid,
             long nativeUiWindowAndroid, boolean forWebVR, VrShellDelegate delegate, long gvrApi,
             boolean reprojectedRendering);
@@ -654,4 +715,6 @@ public class VrShellImpl
     private native void nativeRestoreContentSurface(long nativeVrShell);
     private native void nativeSetHistoryButtonsEnabled(
             long nativeVrShell, boolean canGoBack, boolean canGoForward);
+    private native void nativeRequestUiElementInfoForTesting(
+            long nativeVrShell, String[] elementNames, int callbackId);
 }