Introduce ViewRoot forwarding input/view events to native

ui/android/view_root.cc

Index: ui/android/view_root.cc
diff --git a/ui/android/view_root.cc b/ui/android/view_root.cc
new file mode 100644
index 0000000000000000000000000000000000000000..870e379f7af6ee3866de2021cd088f5b5325974f
--- /dev/null
+++ b/ui/android/view_root.cc
@@ -0,0 +1,143 @@
+// Copyright 2017 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/android/view_root.h"
+
+#include "base/metrics/histogram_macros.h"
+#include "jni/ViewRoot_jni.h"
+#include "ui/display/display.h"
+#include "ui/display/screen.h"
+
+namespace ui {
+
+using base::android::JavaParamRef;
+using base::android::JavaRef;
+
+namespace {
+
+void RecordToolTypeForActionDown(MotionEventAndroid& event) {
+  MotionEventAndroid::Action action = event.GetAction();
+  if (action == MotionEventAndroid::ACTION_DOWN ||
+      action == MotionEventAndroid::ACTION_POINTER_DOWN ||
+      action == MotionEventAndroid::ACTION_BUTTON_PRESS) {
+    UMA_HISTOGRAM_ENUMERATION("Event.AndroidActionDown.ToolType",
+                              event.GetToolType(0),
+                              MotionEventAndroid::TOOL_TYPE_LAST + 1);
+  }
+}
+
+}  // namespace
+
+ViewRoot::ViewRoot(jlong window_android_ptr) {
+  WindowAndroid* window_android =
+          reinterpret_cast<WindowAndroid*>(window_android_ptr);
+  window_ = window_android;
+
+  // ViewRoot simply accepts all events and passes them down to children.
+  SetBounds(gfx::Point(), Bounds::kMatchParent, Bounds::kMatchParent);
+}
+
+void ViewRoot::Destroy(JNIEnv* env, const JavaParamRef<jobject>& obj) {
+  delete this;
+}
+
+ViewAndroid* ViewRoot::GetViewRoot() {
+  return this;
+}
+
+WindowAndroid* ViewRoot::GetWindowAndroid() const {
+  return window_;
+}
+
+void ViewRoot::MoveToFront(ViewAndroid* child) {
+  DCHECK(child);
+  auto it = std::find(children_.begin(), children_.end(), child);
+  DCHECK(it != children_.end());
+
+  if (it != children_.begin()) {
+    children_.erase(it);
+    children_.push_front(*it);
+  }
+}
+
+jboolean ViewRoot::OnTouchEvent(JNIEnv* env,
+                                const JavaParamRef<jobject>& obj,
+                                const JavaParamRef<jobject>& motion_event,
+                                jlong time_ms,
+                                jint android_action,
+                                jint pointer_count,
+                                jint history_size,
+                                jint action_index,
+                                jfloat pos_x_0,
+                                jfloat pos_y_0,
+                                jfloat pos_x_1,
+                                jfloat pos_y_1,
+                                jint pointer_id_0,
+                                jint pointer_id_1,
+                                jfloat touch_major_0,
+                                jfloat touch_major_1,
+                                jfloat touch_minor_0,
+                                jfloat touch_minor_1,
+                                jfloat orientation_0,
+                                jfloat orientation_1,
+                                jfloat tilt_0,
+                                jfloat tilt_1,
+                                jfloat raw_pos_x,
+                                jfloat raw_pos_y,
+                                jint android_tool_type_0,
+                                jint android_tool_type_1,
+                                jint android_button_state,
+                                jint android_meta_state,
+                                jboolean is_touch_handle_event) {
+  MotionEventAndroid::Pointer pointer0(pointer_id_0,
+                                       pos_x_0,
+                                       pos_y_0,
+                                       touch_major_0,
+                                       touch_minor_0,
+                                       orientation_0,
+                                       tilt_0,
+                                       android_tool_type_0);
+  MotionEventAndroid::Pointer pointer1(pointer_id_1,
+                                       pos_x_1,
+                                       pos_y_1,
+                                       touch_major_1,
+                                       touch_minor_1,
+                                       orientation_1,
+                                       tilt_1,
+                                       android_tool_type_1);
+  float dip_scale = display::Screen::GetScreen()
+      ->GetDisplayNearestWindow(this)
+      .device_scale_factor();
+  MotionEventAndroid event(1.f / dip_scale,
+                           env,
+                           motion_event,
+                           time_ms,
+                           android_action,
+                           pointer_count,
+                           history_size,
+                           action_index,
+                           android_button_state,
+                           android_meta_state,
+                           raw_pos_x - pos_x_0,
+                           raw_pos_y - pos_y_0,
+                           &pointer0,
+                           &pointer1);
+
+  RecordToolTypeForActionDown(event);
+
+  return OnTouchEventInternal(event, is_touch_handle_event);
+}
+
+// static
+jlong Init(JNIEnv* env,
+           const JavaParamRef<jobject>& obj,
+           jlong window_android_ptr) {
+  return reinterpret_cast<intptr_t>(new ViewRoot(window_android_ptr));
+}
+
+bool RegisterViewRoot(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}  // namespace ui