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

ui/display/android/display_android_manager.cc

+// Copyright 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.
+
+#include "ui/display/android/display_android_manager.h"
+
+#include <jni.h>
+#include <map>
+
+#include "base/logging.h"
+#include "jni/DisplayAndroidManager_jni.h"
+#include "ui/android/window_android.h"
+#include "ui/display/display.h"
+#include "ui/display/display_export.h"
+#include "ui/display/screen.h"
+
+namespace display {
+
+class DisplayAndroidManager : public Screen {
+ public:
+  DisplayAndroidManager() {}
+  ~DisplayAndroidManager() {}
+
+  // Disallow copy and assign.

[boliu, 2016/11/01 17:11:05]

https://cs.chromium.org/chromium/src/base/macros.h?rcl=0&l=25

[Tima Vaisburd, 2016/11/01 23:04:36]

Done.

+  DisplayAndroidManager(const DisplayAndroidManager& rhs) = delete;
+  DisplayAndroidManager& operator=(const DisplayAndroidManager& rhs) = delete;
+
+  // Screen interface.

[boliu, 2016/11/01 17:11:05]

where are the overrides?

[Tima Vaisburd, 2016/11/01 23:04:36]

Done.

+
+  gfx::Point GetCursorScreenPoint() { return gfx::Point(); }

[boliu, 2016/11/01 17:11:05]

this one is NOTIMPLEMENTED as well

[Tima Vaisburd, 2016/11/01 23:04:36]

Done.

+
+  bool IsWindowUnderCursor(gfx::NativeWindow window) {
+    NOTIMPLEMENTED();
+    return false;
+  }
+
+  gfx::NativeWindow GetWindowAtScreenPoint(const gfx::Point& point) {
+    NOTIMPLEMENTED();
+    return NULL;
+  }
+
+  int GetNumDisplays() const {
+    DCHECK_GE(displays_.size(), 1U);
+    return displays_.size();
+  }
+
+  std::vector<Display> GetAllDisplays() const {
+    DCHECK_GE(displays_.size(), 1U);
+
+    std::vector<Display> result;
+    for (const auto& display : displays_)
+      result.push_back(display.second);
+
+    return result;
+  }
+
+  Display GetDisplayNearestWindow(gfx::NativeView view) const {
+    DCHECK(view);
+    ui::WindowAndroid* window = view->GetWindowAndroid();
+
+    if (window && displays_.count(window->display_id()))
+      return GetFromMap(window->display_id());
+    else
+      return GetPrimaryDisplay();
+  }
+
+  Display GetDisplayNearestPoint(const gfx::Point& point) const {
+    NOTIMPLEMENTED();
+    return Display();

[boliu, 2016/11/01 17:11:05]

old code returns primary display, so keep doing that

but probably should leave some kind of warning like NOTIMPLEMENTED

[Tima Vaisburd, 2016/11/01 23:04:36]

Done.

+  }
+
+  Display GetDisplayMatching(const gfx::Rect& match_rect) const {
+    NOTIMPLEMENTED();
+    return Display();

[boliu, 2016/11/01 17:11:05]

ditto

[Tima Vaisburd, 2016/11/01 23:04:36]

Done.

+  }
+
+  Display GetPrimaryDisplay() const {
+    // Primary display must be set before the first call to this method.
+    CHECK_EQ(displays_.count(primary_display_id_), 1U);

[boliu, 2016/11/01 17:11:04]

since this is a release check, avoid looking up the map twice in release code by
actually using iterators

[Tima Vaisburd, 2016/11/01 23:04:36]

Done.

+    return GetFromMap(primary_display_id_);
+  }
+
+  // Native side observers are not implemented for Android.
+  void AddObserver(DisplayObserver* observer) {}

[boliu, 2016/11/01 17:11:05]

add NOTIMPLEMENTED

[Tima Vaisburd, 2016/11/01 23:04:36]

Done.

+
+  void RemoveObserver(DisplayObserver* observer) {}
+
+  // Helper methods that respond to Java calls.
+
+  void UpdateDisplay(int display_id, const Display& display) {
+    displays_[display_id] = display;
+  }
+
+  void RemoveDisplay(int display_id) { displays_.erase(display_id); }

[boliu, 2016/11/01 17:11:04]

DCHECK key already exists

[Tima Vaisburd, 2016/11/01 23:04:36]

Done.

+
+  void SetPrimaryDisplayId(int display_id) { primary_display_id_ = display_id; }
+
+ private:
+  Display GetFromMap(int id) const {

[boliu, 2016/11/01 17:11:05]

in both places, having this helper is actually forcing the code to do the look
up twice, just don't do it?

[Tima Vaisburd, 2016/11/01 23:04:36]

Done.

+    DCHECK_EQ(displays_.count(id), 1U);

[boliu, 2016/11/01 17:11:05]

fyi there's base::ContainsKey

[Tima Vaisburd, 2016/11/01 23:04:36]

This method is gone, but using in RemoveDisplay().

+    return displays_.find(id)->second;
+  }
+
+  std::map<int, Display> displays_;
+  int primary_display_id_ = 0;
+};
+
+Screen* CreateNativeScreen() {
+  return new DisplayAndroidManager;
+}
+
+bool RegisterDisplayAndroidManager(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+// Called from Java
+
+static void UpdateDisplay(JNIEnv* env,
+                          const base::android::JavaParamRef<jclass>& jcaller,
+                          jint sdkDisplayId,
+                          jint physicalWidth,
+                          jint physicalHeight,
+                          jint width,
+                          jint height,
+                          jfloat dipScale,
+                          jint rotationDegrees,
+                          jint bitsPerPixel,
+                          jint bitsPerComponent) {
+  gfx::Rect bounds_in_pixels = gfx::Rect(physicalWidth, physicalHeight);
+
+  // Physical width and height might be not supported.
+  if (bounds_in_pixels.IsEmpty())
+    bounds_in_pixels = gfx::Rect(width, height);
+
+  const gfx::Rect bounds_in_dip = gfx::Rect(
+      gfx::ScaleToCeiledSize(bounds_in_pixels.size(), 1.0f / dipScale));
+
+  display::Display display = display::Display(0, bounds_in_dip);

[boliu, 2016/11/01 17:11:05]

use id here

also I think declaration syntax might be preferred over assignment, though I
didn't check the style guide.. it's definitely shorter though

[Tima Vaisburd, 2016/11/01 23:04:36]

Done.

+
+  display.set_device_scale_factor(dipScale);
+  display.SetRotationAsDegree(rotationDegrees);
+  display.set_color_depth(bitsPerPixel);
+  display.set_depth_per_component(bitsPerComponent);
+  display.set_is_monochrome(bitsPerComponent == 0);
+
+  static_cast<DisplayAndroidManager*>(Screen::GetScreen())
+      ->UpdateDisplay(sdkDisplayId, display);
+}
+
+static void RemoveDisplay(JNIEnv* env,
+                          const base::android::JavaParamRef<jclass>& jcaller,
+                          jint sdkDisplayId) {
+  static_cast<DisplayAndroidManager*>(Screen::GetScreen())
+      ->RemoveDisplay(sdkDisplayId);
+}
+
+static void SetPrimaryDisplayId(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jclass>& jcaller,
+    jint sdkDisplayId) {
+  static_cast<DisplayAndroidManager*>(Screen::GetScreen())
+      ->SetPrimaryDisplayId(sdkDisplayId);
+}
+
+}  // namespace display