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..7e99903b2f6904967f123e14a6c936f932b5bbe3 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 +61,8 @@ import org.chromium.ui.base.WindowAndroid;
 import org.chromium.ui.display.DisplayAndroid;
 import org.chromium.ui.display.VirtualDisplayAndroid;
 
+import java.util.Iterator;
+
 /**
  * This view extends from GvrLayout which wraps a GLSurfaceView that renders VR shell.
  */
@@ -97,6 +104,10 @@ public class VrShellImpl
     private Surface mSurface;
     private View mPresentationView;
 
+    private SparseArray<Runnable> mUiElementInfoReplyCallbacks;
+    private SparseArray<JSONObject> mUiElementInfoJson;
+    private int mCallbackCounter;
+
     // The tab that holds the main ContentViewCore.
     private Tab mTab;
     private NativePage mNativePage;
@@ -628,6 +639,55 @@ 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

[tiborg, 2017/03/27 15:14:32]

Nit: end sentence with full stop.

[bsheedy, 2017/03/27 17:49:09]

Done.

+    private SparseArray<Runnable> getUiElementInfoReplyCallbacks() {

[tiborg, 2017/03/27 15:14:33]

Should we append ForTesting to make sure it is only used by tests?

[bsheedy, 2017/03/27 17:49:09]

If this is only ever going to be used for testing purposes, sure - are we ever
going to want to get the native state during normal use?

[tiborg, 2017/03/27 19:59:59]

I'm not aware of any plans to use this functionality during normal use. So, I
would append for ForTesting and if we ever want to use it in normal use we just
remove the suffix. 

+        if (mUiElementInfoReplyCallbacks == null) {
+            mUiElementInfoReplyCallbacks = new SparseArray<Runnable>();
+        }
+        return mUiElementInfoReplyCallbacks;
+    }
+
+    // Lazily instantiate since we don't need it in most cases

[tiborg, 2017/03/27 15:14:33]

Nit: end sentence with full stop.

[bsheedy, 2017/03/27 17:49:09]

Done.

+    @VisibleForTesting
+    public SparseArray<JSONObject> getUiElementInfoJson() {

[tiborg, 2017/03/27 15:14:33]

Here, too, append ForTesting?

[bsheedy, 2017/03/27 17:49:09]

Same as above.

+        if (mUiElementInfoJson == null) mUiElementInfoJson = new SparseArray<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 requestUiElementInfoFromNative(int[] elementIds, Runnable onReply) {

[tiborg, 2017/03/27 15:14:33]

Here, too, append ForTesting?

[bsheedy, 2017/03/27 17:49:09]

Same as above.

+        getUiElementInfoReplyCallbacks().append(mCallbackCounter, onReply);
+        nativeRequestUiElementInfo(mNativeVrShell, elementIds, mCallbackCounter);
+        mCallbackCounter++;
+    }
+
+    @CalledByNative
+    public void replyToUiElementInfoRequest(String jsonString, int callbackId)

[tiborg, 2017/03/27 15:14:33]

Here, too, append ForTesting?

[bsheedy, 2017/03/27 17:49:09]

Same as above.

+            throws JSONException {
+        JSONObject reply = new JSONObject(jsonString);
+        SparseArray<JSONObject> uiElementInfo = getUiElementInfoJson();
+        for (Iterator<String> iter = reply.keys(); iter.hasNext();) {
+            String key = iter.next();
+            uiElementInfo.put(Integer.parseInt(key), reply.optJSONObject(key));
+        }
+        SparseArray<Runnable> callbacks = getUiElementInfoReplyCallbacks();
+        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 +714,6 @@ public class VrShellImpl
     private native void nativeRestoreContentSurface(long nativeVrShell);
     private native void nativeSetHistoryButtonsEnabled(
             long nativeVrShell, boolean canGoBack, boolean canGoForward);
+    private native void nativeRequestUiElementInfo(
+            long nativeVrShell, int[] elementIds, int callbackId);
 }