Add a user action for when the home button is clicked.

chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarManager.java

Index: chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarManager.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarManager.java b/chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarManager.java
index b4989841f5ce86f747181428b99ae005c5ccd75f..3c03725416d6537e662c9e1ac6ca5a81174101dc 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarManager.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarManager.java
@@ -863,6 +863,8 @@ public class ToolbarManager implements ToolbarTabController, UrlFocusChangeListe
 
     @Override
     public void openHomepage() {
+        RecordUserAction.record("Home");
+
         Tab currentTab = mToolbarModel.getTab();
         if (currentTab == null) return;
         Context context = mToolbar.getContext();