[Contextual Search] Keep Panel upon orientation change.

chrome/android/java/src/org/chromium/chrome/browser/compositor/bottombar/OverlayPanel.java

Index: chrome/android/java/src/org/chromium/chrome/browser/compositor/bottombar/OverlayPanel.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/compositor/bottombar/OverlayPanel.java b/chrome/android/java/src/org/chromium/chrome/browser/compositor/bottombar/OverlayPanel.java
index c519959ad2457e0b68058243cf77f7f26be48a88..631f21a454f0076fc1b93cdc606f960e109a71ed 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/compositor/bottombar/OverlayPanel.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/compositor/bottombar/OverlayPanel.java
@@ -314,7 +314,7 @@ public class OverlayPanel extends ContextualSearchPanelAnimation
      */
     private OverlayPanelContent createNewOverlayPanelContentInternal() {
         OverlayPanelContent content = mContentFactory.createNewOverlayPanelContent();
-        // Adds a ContentViewClient to override the default fullscreen size.
+
         content.setContentViewClient(new ContentViewClient() {
             @Override
             public int getDesiredWidthMeasureSpec() {
@@ -338,6 +338,7 @@ public class OverlayPanel extends ContextualSearchPanelAnimation
                 }
             }
         });
+
         return content;
     }
 
@@ -490,6 +491,32 @@ public class OverlayPanel extends ContextualSearchPanelAnimation
         return true;
     }
 
+    /**
+     * Handles the device orientation change.
+     */
+    public void onOrientationChanged() {
+        if (isNarrowSizePanelSupported()) {
+            // TODO(pedrosimonetti): We cannot preserve the panel when rotating from/to a
+            // narrow version of the Panel because the Content is resized before the Panel
+            // gets a notification of the resize.
+            closePanel(StateChangeReason.UNKNOWN, false);
+        } else {
+            updatePanelForOrientationChange();
+        }
+    }
+
+    /**
+     * Updates the Panel so it preserves its state when the orientation changes.
+     */
+    protected void updatePanelForOrientationChange() {
+        // NOTE(pedrosimonetti): We cannot tell where the selection will be after the
+        // orientation change, so we are setting the selection position to zero, which
+        // means the base page will be positioned in its original state and we won't
+        // try to keep the selection in view.
+        updateBasePageSelectionYPx(0.f);
+        resizePanelToState(getPanelState(), StateChangeReason.UNKNOWN);
+    }
+
     // ============================================================================================
     // Generic Event Handling
     // ============================================================================================