Fix of flaky SdchTest#testSdchEnabled test.

components/cronet/android/test/src/org/chromium/net/SdchObserver.java

Index: components/cronet/android/test/src/org/chromium/net/SdchObserver.java
diff --git a/components/cronet/android/test/src/org/chromium/net/SdchObserver.java b/components/cronet/android/test/src/org/chromium/net/SdchObserver.java
index 8e8fe127baab8542b42cf87bff6798284d80d1b4..2028c09040c7b3170ade5627ea3dd9974c8058ec 100644
--- a/components/cronet/android/test/src/org/chromium/net/SdchObserver.java
+++ b/components/cronet/android/test/src/org/chromium/net/SdchObserver.java
@@ -6,6 +6,8 @@ package org.chromium.net;
 
 import android.os.ConditionVariable;
 
+import junit.framework.Assert;
+
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
 
@@ -13,11 +15,10 @@ import org.chromium.base.annotations.JNINamespace;
  * Class to watch for Sdch dictionary events. The native implementation
  * unregisters itself when an event happens. Therefore, an instance of this
  * class is only able to receive a notification of the earliest event.
- * Currently, implemented events include {@link #onDictionaryAdded}.
  */
 @JNINamespace("cronet")
 public class SdchObserver {
-    protected boolean mDictionaryAlreadyPresent = false;
+    private static final int BLOCK_WAIT_TIMEOUT_SEC = 20;
     private final ConditionVariable mAddBlock = new ConditionVariable();
 
     /**
@@ -27,29 +28,39 @@ public class SdchObserver {
      */
     public SdchObserver(String targetUrl, long contextAdapter) {
         nativeAddSdchObserver(targetUrl, contextAdapter);
-        mAddBlock.block();
-        mAddBlock.close();
     }
 
     /**
      * Called when a dictionary is added to the SdchManager for the target url.
-     * Override this method if caller would like to get notified.
      */
     @CalledByNative
-    public void onDictionaryAdded() {
-        // Left blank;
+    protected void onDictionaryAdded() {
+        mAddBlock.open();
     }
 
+    /**
+     * Called after the observer has been registered.
+     */
     @CalledByNative
-    private void onAddSdchObserverCompleted() {
-        mAddBlock.open();
+    protected void onAddSdchObserverCompleted() {
+        // Left blank;
     }
 
+    /**
+     * Called if the dictionary was added before the observer registration.
+     */
     @CalledByNative
-    private void onDictionarySetAlreadyPresent() {
-        mDictionaryAlreadyPresent = true;
+    protected void onDictionarySetAlreadyPresent() {
         mAddBlock.open();
     }
 
+    public void waitForDictionaryAdded() {
+        boolean success = mAddBlock.block(BLOCK_WAIT_TIMEOUT_SEC * 1000);
+        if (!success) {
+            Assert.fail("Timeout: the dictionary hasn't been added after waiting for "
+                    + BLOCK_WAIT_TIMEOUT_SEC + " seconds");
+        }
+    }
+
     private native void nativeAddSdchObserver(String targetUrl, long contextAdapter);
 }