Cache DeviceDisplayInfo data in shared structure on native side to avoid frequent JNI calls.

ui/gfx/android/device_display_info.h

 // Copyright (c) 2012 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 UI_GFX_ANDROID_DEVICE_DISPLAY_INFO_H_
 #define UI_GFX_ANDROID_DEVICE_DISPLAY_INFO_H_
 
 #include <jni.h>
 #include <string>
 
-#include "base/android/scoped_java_ref.h"
 #include "base/basictypes.h"
 #include "ui/gfx/gfx_export.h"
 
 namespace gfx {
 
 // Facilitates access to device information typically only
 // available using the Android SDK, including Display properties.
 class GFX_EXPORT DeviceDisplayInfo {
  public:
   DeviceDisplayInfo();
   ~DeviceDisplayInfo();
 
   // Returns display height in physical pixels.
   int GetDisplayHeight();
 
   // Returns display width in physical pixels.
   int GetDisplayWidth();
 
   // Returns number of bits per pixel.
   int GetBitsPerPixel();
 
   // Returns number of bits per component.
   int GetBitsPerComponent();
 
   // Returns a scaling factor for Density Independent Pixel unit
   // (1.0 is 160dpi, 0.75 is 120dpi, 2.0 is 320dpi).
   double GetDIPScale();
 
-  // Registers methods with JNI and returns true if succeeded.
-  static bool RegisterDeviceDisplayInfo(JNIEnv* env);
-
  private:
-  base::android::ScopedJavaGlobalRef<jobject> j_device_info_;
-
   DISALLOW_COPY_AND_ASSIGN(DeviceDisplayInfo);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_ANDROID_DEVICE_DISPLAY_INFO_H_