Hide the page info dialog if the underlying webcontents is hidden.

content/public/android/java/src/org/chromium/content_public/browser/WebContentsObserver.java

Index: content/public/android/java/src/org/chromium/content_public/browser/WebContentsObserver.java
diff --git a/content/public/android/java/src/org/chromium/content_public/browser/WebContentsObserver.java b/content/public/android/java/src/org/chromium/content_public/browser/WebContentsObserver.java
index 0a42bb0eb27eed87a6b69a4a7942f63037ec8b90..5dd8096fe2b16e97b4037eb895b5a35d19ed187c 100644
--- a/content/public/android/java/src/org/chromium/content_public/browser/WebContentsObserver.java
+++ b/content/public/android/java/src/org/chromium/content_public/browser/WebContentsObserver.java
@@ -83,6 +83,16 @@ public abstract class WebContentsObserver {
     public void didFirstVisuallyNonEmptyPaint() {}
 
     /**
+     * The web contents was shown.
+     */
+    public void wasShown() {}
+
+    /**
+     * The web contents was hidden.
+     */
+    public void wasHidden() {}
+
+    /**
      * Similar to didNavigateMainFrame but also called on subframe navigations.
      * @param url The validated url for the page.
      * @param baseUrl The validated base url for the page.