Bug 1307816 - 9. Fix IC thread switching after async refactoring; r=esawin

When switching the IC thread from one thread to another, we can no
longer block on the old IC thread waiting for the Gecko thread. However,
we still block on the new IC thread, waiting for the old IC thread to
finish processing any old events.

mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoEditable.java

@@ -594,6 +594,7 @@ final class GeckoEditable extends JNIObject
         // Post to UI thread first to make sure any code that is using the old input
         // connection has finished running, before we switch to a new input connection or
         // before we clear the input connection on destruction.
+        final Handler icHandler = mIcPostHandler;
         ThreadUtils.postToUiThread(new Runnable() {
             @Override
             public void run() {
@@ -611,7 +612,7 @@ final class GeckoEditable extends JNIObject
                 }
 
                 mView = v;
-                mIcPostHandler.post(setListenerRunnable);
+                icHandler.post(setListenerRunnable);
             }
         });
     }
@@ -625,6 +626,9 @@ final class GeckoEditable extends JNIObject
     }
 
     private void geckoPostToIc(Runnable runnable) {
+        if (DEBUG) {
+            ThreadUtils.assertOnGeckoThread();
+        }
         mIcPostHandler.post(runnable);
     }
 
@@ -890,14 +894,15 @@ final class GeckoEditable extends JNIObject
         mSuppressKeyUp = suppress;
     }
 
-    @Override
-    public Handler setInputConnectionHandler(Handler handler) {
-        if (handler == mIcPostHandler || !mFocused) {
-            return mIcPostHandler;
+    @Override // GeckoEditableClient
+    public Handler setInputConnectionHandler(final Handler handler) {
+        if (handler == mIcRunHandler) {
+            return mIcRunHandler;
         }
         if (DEBUG) {
             assertOnIcThread();
         }
+
         // There are three threads at this point: Gecko thread, old IC thread, and new IC
         // thread, and we want to safely switch from old IC thread to new IC thread.
         // We first send a TYPE_SET_HANDLER action to the Gecko thread; this ensures that
@@ -910,6 +915,21 @@ final class GeckoEditable extends JNIObject
         // also post a Runnable to the new IC thread; this Runnable blocks until the
         // switch is complete; this ensures that the new IC thread won't accept
         // InputConnection calls until after the switch.
+
+        handler.post(new Runnable() { // Make the new IC thread wait.
+            @Override
+            public void run() {
+                synchronized (handler) {
+                    while (mIcRunHandler != handler) {
+                        try {
+                            handler.wait();
+                        } catch (final InterruptedException e) {
+                        }
+                    }
+                }
+            }
+        });
+
         icOfferAction(Action.newSetHandler(handler));
         return handler;
     }
@@ -939,20 +959,6 @@ final class GeckoEditable extends JNIObject
         // we don't switch mIcRunHandler yet because there may be pending Runnables on the
         // old IC thread still waiting to run.
         mIcPostHandler = newHandler;
-
-        geckoPostToIc(new Runnable() { // posting to new IC thread
-            @Override
-            public void run() {
-                synchronized (newHandler) {
-                    while (mIcRunHandler != newHandler) {
-                        try {
-                            newHandler.wait();
-                        } catch (InterruptedException e) {
-                        }
-                    }
-                }
-            }
-        });
     }
 
     private void geckoActionReply(final Action action) {