Add MemoryMonitorAndroid

content/browser/memory/memory_monitor_android.h

Index: content/browser/memory/memory_monitor_android.h
diff --git a/content/browser/memory/memory_monitor_android.h b/content/browser/memory/memory_monitor_android.h
index 3d983ac56e4a4dde4701c20f8f1cc9cf23abd663..abd7824c1ae42ab86977fdb4af3b57db71c8f702 100644
--- a/content/browser/memory/memory_monitor_android.h
+++ b/content/browser/memory/memory_monitor_android.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2016 The Chromium Authors. All rights reserved.
+// Copyright 2016 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.
 
@@ -16,12 +16,14 @@ class CONTENT_EXPORT MemoryMonitorAndroid : public MemoryMonitor {
  public:
   static std::unique_ptr<MemoryMonitorAndroid> Create();
 
+  static bool Register(JNIEnv* env);
+
   // C++ counter-part of ActivityManager.MemoryInfo
   struct MemoryInfo {
-    long avail_mem;
-    bool low_memory;
-    long threshold;
-    long total_mem;
+    jlong avail_mem;
+    jboolean low_memory;
+    jlong threshold;
+    jlong total_mem;
   };
 
   ~MemoryMonitorAndroid() override;
@@ -29,23 +31,12 @@ class CONTENT_EXPORT MemoryMonitorAndroid : public MemoryMonitor {
   // MemoryMonitor implementation:
   int GetFreeMemoryUntilCriticalMB() override;
 
-  // Returns true when this class can get memory info from the Android system.
-  bool CanGetMemoryInfo();
   // Get memory info from the Android system.
   void GetMemoryInfo(MemoryInfo* out);
 
  private:
   MemoryMonitorAndroid();
 
-  // Initializes field IDs of ActivityManager.MemoryInfo
-  void InitializeFieldIDs();
-
-  // Field IDs for ActivityManager.MemoryInfo
-  jfieldID avail_mem_id_ = 0;
-  jfieldID low_memory_id_ = 0;
-  jfieldID threshold_id_ = 0;
-  jfieldID total_mem_id_ = 0;
-
   DISALLOW_COPY_AND_ASSIGN(MemoryMonitorAndroid);
 };