Adds MemoryPressureListener.

base/android/java/src/org/chromium/base/MemoryPressureListener.java

Index: base/android/java/src/org/chromium/base/MemoryPressureListener.java
diff --git a/base/android/java/src/org/chromium/base/MemoryPressureListener.java b/base/android/java/src/org/chromium/base/MemoryPressureListener.java
new file mode 100644
index 0000000000000000000000000000000000000000..f34f36d695fb73369afc80cfeabac8d1be18f32a
--- /dev/null
+++ b/base/android/java/src/org/chromium/base/MemoryPressureListener.java
@@ -0,0 +1,48 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.base;
+
+import android.content.ComponentCallbacks2;
+import android.content.Context;
+import android.content.res.Configuration;
+
+import org.chromium.base.MemoryPressureLevelList;
+
+
+/**
+ * This is an internal implementation of the C++ counterpart.
+ * It registers a ComponentCallbacks2 with the system, and dispatches into
+ * native.
+ */
+class MemoryPressureListener {
+  @CalledByNative
+  private static void registerSystemCallback(Context context) {
+      context.registerComponentCallbacks(
+          new ComponentCallbacks2() {
+                @Override
+                public void onTrimMemory(int level) {
+                    nativeOnMemoryPressure(translate(level));
+                }
+
+                @Override
+                public void onLowMemory() {
+                    nativeOnMemoryPressure(MemoryPressureLevelList.MEMORY_PRESSURE_CRITICAL);
+                }
+
+                @Override
+                public void onConfigurationChanged(Configuration configuration) {
+                }
+          });
+  }
+
+  private static int translate(int level) {
+      if (level == ComponentCallbacks2.TRIM_MEMORY_COMPLETE) {
+          return MemoryPressureLevelList.MEMORY_PRESSURE_CRITICAL;
+      }
+      return MemoryPressureLevelList.MEMORY_PRESSURE_MODERATE;
+  }
+
+  private static native void nativeOnMemoryPressure(int memoryPressureType);
+}