Reland of Android: support multiple displays on C++ side

ui/android/display_android_manager.h

+// 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.
+
+#ifndef UI_ANDROID_DISPLAY_ANDROID_MANAGER_H_
+#define UI_ANDROID_DISPLAY_ANDROID_MANAGER_H_
+
+#include <jni.h>
+#include <map>
+
+#include "base/android/jni_android.h"
+#include "base/macros.h"
+#include "ui/display/screen.h"
+
+namespace ui {
+
+class DisplayAndroidManager : public display::Screen {
+ public:
+  ~DisplayAndroidManager() override;
+
+  // Screen interface.
+
+  gfx::Point GetCursorScreenPoint() override;
+  bool IsWindowUnderCursor(gfx::NativeWindow window) override;
+  gfx::NativeWindow GetWindowAtScreenPoint(const gfx::Point& point) override;
+  int GetNumDisplays() const override;
+  std::vector<display::Display> GetAllDisplays() const override;
+  display::Display GetDisplayNearestWindow(gfx::NativeView view) const override;
+  display::Display GetDisplayNearestPoint(
+      const gfx::Point& point) const override;
+  display::Display GetDisplayMatching(
+      const gfx::Rect& match_rect) const override;
+  display::Display GetPrimaryDisplay() const override;
+  void AddObserver(display::DisplayObserver* observer) override;
+  void RemoveObserver(display::DisplayObserver* observer) override;
+
+  // Methods called from Java.
+
+  void UpdateDisplay(JNIEnv* env,
+                     const base::android::JavaParamRef<jobject>& jobject,
+                     jint sdkDisplayId,
+                     jint physicalWidth,
+                     jint physicalHeight,
+                     jint width,
+                     jint height,
+                     jfloat dipScale,
+                     jint rotationDegrees,
+                     jint bitsPerPixel,
+                     jint bitsPerComponent);
+  void RemoveDisplay(JNIEnv* env,
+                     const base::android::JavaParamRef<jobject>& jobject,
+                     jint sdkDisplayId);
+  void SetPrimaryDisplayId(JNIEnv* env,
+                           const base::android::JavaParamRef<jobject>& jobject,
+                           jint sdkDisplayId);
+
+ private:
+  friend void SetScreenAndroid();
+  DisplayAndroidManager();
+
+  using DisplayMap = std::map<int, display::Display>;
+  DisplayMap displays_;
+  int primary_display_id_ = 0;
+
+  DISALLOW_COPY_AND_ASSIGN(DisplayAndroidManager);
+};
+
+}  // namespace ui
+
+#endif  // UI_ANDROID_DISPLAY_ANDROID_MANAGER_H_