[Android] Additional events to observe in TabObserver.

chrome/android/java/src/org/chromium/chrome/browser/Tab.java

Index: chrome/android/java/src/org/chromium/chrome/browser/Tab.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/Tab.java b/chrome/android/java/src/org/chromium/chrome/browser/Tab.java
index 1bc34eb2be5b7d3df13137e30d30e57c1e3af35d..958b5f8f52c5e67829772a430570011226ef82ee 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/Tab.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/Tab.java
@@ -157,6 +157,16 @@ public abstract class Tab implements NavigationClient {
         }
 
         @Override
+        public void onLoadStarted() {
+            for (TabObserver observer : mObservers) observer.onLoadStarted(Tab.this);
+        }
+
+        @Override
+        public void onLoadStopped() {
+            for (TabObserver observer : mObservers) observer.onLoadStopped(Tab.this);
+        }
+
+        @Override
         public void onUpdateUrl(String url) {
             for (TabObserver observer : mObservers) observer.onUpdateUrl(Tab.this, url);
         }