Add a cache for recently viewed webpages.

chrome/android/java/src/org/chromium/chrome/browser/historyreport/AppIndexingReporter.java

Index: chrome/android/java/src/org/chromium/chrome/browser/historyreport/AppIndexingReporter.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/historyreport/AppIndexingReporter.java b/chrome/android/java/src/org/chromium/chrome/browser/historyreport/AppIndexingReporter.java
index 92670c0da9f39e2ab5b6c8ebf96076ec42fd4ca5..a50ca8d418c7fea8d8b97a59df3ddc7eee72f008 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/historyreport/AppIndexingReporter.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/historyreport/AppIndexingReporter.java
@@ -29,6 +29,15 @@ public class AppIndexingReporter {
     }
 
     /**
+     * Reports view of provided url to on-device index.
+     * Base class does not implement any reporting, and call is a no-op. Child classes should
+     * implement this functionality.
+     */
+    public void reportWebPageView(String url, String title) {
+        // Overriden by private class. Base class does nothing.
+    }
+
+    /**
      * Clears history of reported entities.
      * Currently, we do not support clearing only a subset of history. Base class does not implement
      * any reporting, and call is a no-op. Child classes should implement this functionality.