Add EventForwarder for routing touch events

content/browser/android/event_forwarder_impl.cc

+// 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 "content/browser/android/event_forwarder_impl.h"
+
+#include "base/metrics/histogram_macros.h"
+#include "content/browser/renderer_host/render_widget_host_view_android.h"
+#include "content/browser/web_contents/web_contents_impl.h"
+#include "content/browser/web_contents/web_contents_view.h"
+#include "content/public/browser/interstitial_page.h"
+#include "jni/EventForwarderImpl_jni.h"
+
+using base::android::JavaParamRef;
+using ui::MotionEventAndroid;
+
+namespace content {
+
+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
+
+EventForwarderImpl::EventForwarderImpl(WebContentsImpl* web_contents)
+    : web_contents_(web_contents) {
+  dip_scale_ = GetViewAndroid()->GetDipScale();
+}
+
+jboolean EventForwarderImpl::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) {
+  RenderWidgetHostViewAndroid* rwhv = GetRenderWidgetHostViewAndroid();
+  // Avoid synthesizing a touch event if it cannot be forwarded.
+  if (!rwhv)
+    return false;
+
+  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);
+  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 is_touch_handle_event ? rwhv->OnTouchHandleEvent(event)

[boliu, 2017/02/21 16:23:30]

this isn't actually using the viewandroid tree to forward events?

[Jinsuk Kim, 2017/02/26 23:18:27]

Done.

+                               : rwhv->OnTouchEvent(event);
+}
+
+ui::ViewAndroid* EventForwarderImpl::GetViewAndroid() const {
+  return web_contents_->GetView()->GetNativeView();
+}
+
+RenderWidgetHostViewAndroid*
+EventForwarderImpl::GetRenderWidgetHostViewAndroid() const {
+  RenderWidgetHostView* rwhv = nullptr;
+  rwhv = web_contents_->GetRenderWidgetHostView();
+  if (web_contents_->ShowingInterstitialPage()) {
+    rwhv = web_contents_->GetInterstitialPage()
+               ->GetMainFrame()
+               ->GetRenderViewHost()
+               ->GetWidget()
+               ->GetView();
+  }
+  return static_cast<RenderWidgetHostViewAndroid*>(rwhv);
+}
+
+jlong Init(JNIEnv* env,
+           const JavaParamRef<jobject>& obj,
+           const JavaParamRef<jobject>& jweb_contents) {
+  WebContentsImpl* web_contents = static_cast<WebContentsImpl*>(
+      WebContents::FromJavaWebContents(jweb_contents));
+  CHECK(web_contents)
+      << "An EventFowarder should be created with a valid WebContents.";
+  return reinterpret_cast<intptr_t>(new EventForwarderImpl(web_contents));
+}
+
+bool RegisterEventForwarderImpl(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}  // namespace content