Adds MemoryPressureListener.

base/android/memory_pressure_handler_android.h

Index: base/android/memory_pressure_handler_android.h
diff --git a/base/android/memory_pressure_handler_android.h b/base/android/memory_pressure_handler_android.h
new file mode 100644
index 0000000000000000000000000000000000000000..22b2e18b3b0833e90c75d3c96b4f6bce71115ca5
--- /dev/null
+++ b/base/android/memory_pressure_handler_android.h
@@ -0,0 +1,30 @@
+// 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.
+
+#ifndef CHROME_BROWSER_ANDROID_MEMORY_PRESSURE_HANDLER_ANDROID_H_
+#define CHROME_BROWSER_ANDROID_MEMORY_PRESSURE_HANDLER_ANDROID_H_

[joth, 2013/06/05 19:28:58]

is this guy still a 'handler' ?

[bulach, 2013/06/06 09:28:30]

renamed to memory_pressure_android (and fixed the include header..)

+
+#include "base/android/jni_android.h"
+
+namespace base {
+namespace android {
+
+// Implements the C++ counter part of MemoryPressureHandler.java
+class MemoryPressureHandlerAndroid {
+ public:
+  static bool Register(JNIEnv* env);
+
+  static void RegisterSystemCallback(JNIEnv* env);

[joth, 2013/06/05 19:28:58]

rather than require embedder to call this, we could do it from within the cross
platform MemoryPressureNotifier's constructor. (naive approach: just have it
call some static PlatInit() method that each platform implements as they like).
This maybe racy if we don't setup Application Context right away on startup, but
I think we do.

Anyway, I don't have strong pref eitherway on this.

[joth, 2013/06/05 19:49:48]

but nead caution if we do this as we (probably) want to be sure the java
notifier gets hooked up on the UI thread. Can easily do that with
ThreadUtils.runOnUiThread() I guess.

[bulach, 2013/06/06 09:28:30]

I'd rather keep it simple for the time being.. once / if CrOS hook up their
low-memory signals, we can certain review this in a way to accommodate the
platform-specific bits..

+
+  // Called by JNI.
+  static void OnMemoryPressure(int memory_pressure_type);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MemoryPressureHandlerAndroid);
+};
+
+}  // namespace android
+}  // namespace base
+
+#endif  // CHROME_BROWSER_ANDROID_MEMORY_PRESSURE_HANDLER_ANDROID_H_