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 e41fd281fdd18c848557091dda0ea3c03bb86a93..dbe71126a8b7336462bd5c96a6597e73832cc985 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
@@ -853,6 +853,8 @@ 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();