Poll for Display rotation on Android 4.0 and 4.1 when needed.

content/public/android/java/src/org/chromium/content/browser/ScreenOrientationListener.java

Index: content/public/android/java/src/org/chromium/content/browser/ScreenOrientationListener.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/ScreenOrientationListener.java b/content/public/android/java/src/org/chromium/content/browser/ScreenOrientationListener.java
index 7e809c0e27578f5fdbf9ebe9cdd67fe464869d66..cb0cd5fe7cdb96d562966998466ac7119a2e2e6e 100644
--- a/content/public/android/java/src/org/chromium/content/browser/ScreenOrientationListener.java
+++ b/content/public/android/java/src/org/chromium/content/browser/ScreenOrientationListener.java
@@ -60,6 +60,13 @@ public class ScreenOrientationListener {
          * when the last observer is removed.
          */
         void stopListening();
+
+        /**
+         * Toggle the accurate mode. Starts listening accurately if the listener
+         * wasn't or stop doing so if it was. This might be a no-op if the
+         * listener always listen accurately.
+         */
+        void toggleAccurateMode();
     }
 
     /**
@@ -69,10 +76,16 @@ public class ScreenOrientationListener {
      *
      * This method is known to not correctly detect 180 degrees changes but it
      * is the only method that will work before API Level 17 (excluding polling).
+     * When toggleAccurateMode() is called, it will start polling in order to
+     * find out if the display has changed.
      */
     private class ScreenOrientationConfigurationListener
             implements ScreenOrientationListenerBackend, ComponentCallbacks {
 
+        private static final long POLLING_DELAY = 500;
+
+        private boolean mAccurateMode = false;
+
         // ScreenOrientationListenerBackend implementation:
 
         @Override
@@ -85,6 +98,29 @@ public class ScreenOrientationListener {
             mAppContext.unregisterComponentCallbacks(this);
         }
 
+        @Override
+        public void toggleAccurateMode() {
+            // If mAccurateMode is set to true, a Runnable will be started and
+            // will get restarted every POLLING_DELAY until mAccurateMode is set
+            // to false.
+            mAccurateMode = !mAccurateMode;
+
+            if (mAccurateMode) {
+                final ScreenOrientationConfigurationListener self = this;
+                ThreadUtils.postOnUiThreadDelayed(new Runnable() {
+                    @Override
+                    public void run() {
+                        self.onConfigurationChanged(null);
+
+                        if (self.mAccurateMode) {
+                            ThreadUtils.postOnUiThreadDelayed(this,
+                                    ScreenOrientationConfigurationListener.POLLING_DELAY);
+                        }
+                    }
+                }, POLLING_DELAY);
+            }
+        }
+
         // ComponentCallbacks implementation:
 
         @Override
@@ -123,6 +159,11 @@ public class ScreenOrientationListener {
             displayManager.unregisterDisplayListener(this);
         }
 
+        @Override
+        public void toggleAccurateMode() {
+            // Always accurate. Do nothing.
+        }
+
         // DisplayListener implementation:
 
         @Override
@@ -244,6 +285,15 @@ public class ScreenOrientationListener {
     }
 
     /**
+     * Toggle the accurate mode. Starts listening accurately if the listener
+     * wasn't or stop doing so if it was. This might be a no-op if the
+     * listener always listen accurately.
+     */
+    public void toggleAccurateMode() {
+        mBackend.toggleAccurateMode();
+    }
+
+    /**
      * This should be called by classes extending ScreenOrientationListener when
      * it is possible that there is a screen orientation change. If there is an
      * actual change, the observers will get notified.
@@ -252,12 +302,12 @@ public class ScreenOrientationListener {
         int previousOrientation = mOrientation;
         updateOrientation();
 
-        DeviceDisplayInfo.create(mAppContext).updateNativeSharedDisplayInfo();
-
         if (mOrientation == previousOrientation) {
             return;
         }
 
+        DeviceDisplayInfo.create(mAppContext).updateNativeSharedDisplayInfo();
+
         for (ScreenOrientationObserver observer : mObservers) {
             observer.onScreenOrientationChanged(mOrientation);
         }