Adds MemoryPressureListener.

content/shell/android/shell_apk/src/org/chromium/content_shell_apk/ContentShellActivity.java

Index: content/shell/android/shell_apk/src/org/chromium/content_shell_apk/ContentShellActivity.java
diff --git a/content/shell/android/shell_apk/src/org/chromium/content_shell_apk/ContentShellActivity.java b/content/shell/android/shell_apk/src/org/chromium/content_shell_apk/ContentShellActivity.java
index 9dc2bcef461339863468b092e4c2756afaa3b278..f0ba0029178348def39dba45cb831b8b96083e1b 100644
--- a/content/shell/android/shell_apk/src/org/chromium/content_shell_apk/ContentShellActivity.java
+++ b/content/shell/android/shell_apk/src/org/chromium/content_shell_apk/ContentShellActivity.java
@@ -14,6 +14,7 @@ import android.util.Log;
 import android.view.KeyEvent;
 
 import org.chromium.base.ChromiumActivity;
+import org.chromium.base.MemoryPressureHandler;
 import org.chromium.content.app.LibraryLoader;
 import org.chromium.content.browser.ActivityContentVideoViewDelegate;
 import org.chromium.content.browser.AndroidBrowserProcess;
@@ -181,6 +182,11 @@ public class ContentShellActivity extends ChromiumActivity {
         mWindowAndroid.onActivityResult(requestCode, resultCode, data);
     }
 
+    @Override
+    public void onTrimMemory(int level) {
+        MemoryPressureHandler.onMemoryPressure(level);
+    }
+
     private static String getUrlFromIntent(Intent intent) {
         return intent != null ? intent.getDataString() : null;
     }