Add a full Blimp integration test.

blimp/client/core/contents/android/java/src/org/chromium/blimp/core/contents/BlimpContentsObserverProxy.java

Index: blimp/client/core/contents/android/java/src/org/chromium/blimp/core/contents/BlimpContentsObserverProxy.java
diff --git a/blimp/client/core/contents/android/java/src/org/chromium/blimp/core/contents/BlimpContentsObserverProxy.java b/blimp/client/core/contents/android/java/src/org/chromium/blimp/core/contents/BlimpContentsObserverProxy.java
index 21546472b909b37307278414ca1a4098324d0822..b3212ab269dc48e4f471ff1099f87202ca275397 100644
--- a/blimp/client/core/contents/android/java/src/org/chromium/blimp/core/contents/BlimpContentsObserverProxy.java
+++ b/blimp/client/core/contents/android/java/src/org/chromium/blimp/core/contents/BlimpContentsObserverProxy.java
@@ -56,6 +56,14 @@ class BlimpContentsObserverProxy implements BlimpContentsObserver {
         }
     }
 
+    @Override
+    @CalledByNative
+    public void onPageLoadingStateChanged(boolean loading) {
+        for (BlimpContentsObserver observer : mObservers) {
+            observer.onPageLoadingStateChanged(loading);
+        }
+    }
+
     private native long nativeInit(BlimpContentsImpl blimpContentsImpl);
     private native void nativeDestroy(long nativeBlimpContentsObserverProxy);
 }