Add EventForwarder for routing touch events

ui/android/view_android.cc

Index: ui/android/view_android.cc
diff --git a/ui/android/view_android.cc b/ui/android/view_android.cc
index 1d5b146653458a83b93c58810f743f6df78e5c46..9b1e47a797a77b9e5fa8257a2b0bfb74ee17ff53 100644
--- a/ui/android/view_android.cc
+++ b/ui/android/view_android.cc
@@ -10,9 +10,10 @@
 #include "base/android/jni_string.h"
 #include "cc/layers/layer.h"
 #include "jni/ViewAndroidDelegate_jni.h"
+#include "ui/android/event_handler.h"
+#include "ui/android/view_client.h"
 #include "ui/android/window_android.h"
-#include "ui/display/display.h"
-#include "ui/display/screen.h"
+#include "ui/base/layout.h"
 #include "url/gurl.h"
 
 namespace ui {
@@ -71,11 +72,12 @@ ViewAndroid::ScopedAnchorView::view() const {
   return view_.get(env);
 }
 
-ViewAndroid::ViewAndroid(const JavaRef<jobject>& delegate)
+ViewAndroid::ViewAndroid(ViewClient* view_client)
     : parent_(nullptr),
-      delegate_(base::android::AttachCurrentThread(), delegate.obj()) {}
+      client_(view_client),
+      dip_scale_(ui::GetScaleFactorForNativeView(this)) {}

[boliu, 2017/02/27 19:21:57]

again, don't cache this

[Jinsuk Kim, 2017/02/28 06:56:04]

Done.

 
-ViewAndroid::ViewAndroid() : parent_(nullptr) {}
+ViewAndroid::ViewAndroid() : ViewAndroid(nullptr) {}
 
 ViewAndroid::~ViewAndroid() {
   RemoveFromParent();
@@ -88,21 +90,48 @@ ViewAndroid::~ViewAndroid() {
 }
 
 void ViewAndroid::SetDelegate(const JavaRef<jobject>& delegate) {
+  // A ViewAndroid may have its own delegate or otherwise will
+  // use the next available parent's delegate.
   JNIEnv* env = base::android::AttachCurrentThread();
   delegate_ = JavaObjectWeakGlobalRef(env, delegate);
 }
 
+float ViewAndroid::GetDipScale() {
+  return dip_scale_;
+}
+
+EventHandler* ViewAndroid::CreateEventHandler() {
+  DCHECK(!parent_ || parent_ == GetWindowAndroid())

[boliu, 2017/02/27 19:21:57]

this is gonna break after WCVA is not immediate child of root

use the original condition, that a root can have at most one source of events

[Jinsuk Kim, 2017/02/28 06:56:04]

Done. Restored |GetViewRoot()| that returns the top of the view tree where the
event forwarding gets started for this content.

+      << "Only WebContentViewAndroid's ViewAndroid can have event handler.";
+  DCHECK(!event_handler_) << "EventHandler is already created";
+
+  event_handler_.reset(EventHandler::Create(this));
+  return event_handler_.get();
+}
+
 void ViewAndroid::AddChild(ViewAndroid* child) {
   DCHECK(child);
   DCHECK(std::find(children_.begin(), children_.end(), child) ==
          children_.end());
+  DCHECK(!ViewTreeHasEventHandler(child)) << "Child cannot have event handler";

[boliu, 2017/02/27 19:21:57]

why not..? that only holds if we don't already have a event handler

[Jinsuk Kim, 2017/02/28 06:56:04]

The restriction was to allow for the event handler only to WCVA's VA. I guess
you want it more general... Done.

 
+  // The new child goes to the top, which is the end of the list.
   children_.push_back(child);
   if (child->parent_)
     child->RemoveFromParent();
   child->parent_ = this;
 }
 
+bool ViewAndroid::ViewTreeHasEventHandler(ViewAndroid* view) {
+  if (view->has_event_handler())
+    return true;
+  for (auto& child : view->children_) {
+    if (child->has_event_handler())
+      return true;
+  }
+  return false;
+}
+
 void ViewAndroid::RemoveFromParent() {
   if (parent_)
     parent_->RemoveChild(this);
@@ -124,15 +153,12 @@ void ViewAndroid::SetAnchorRect(const JavaRef<jobject>& anchor,
   if (delegate.is_null())
     return;
 
-  float scale = display::Screen::GetScreen()
-                    ->GetDisplayNearestWindow(this)
-                    .device_scale_factor();
-  int left_margin = std::round(bounds.x() * scale);
-  int top_margin = std::round((content_offset().y() + bounds.y()) * scale);
+  int left_margin = std::round(bounds.x() * dip_scale_);
+  int top_margin = std::round((content_offset().y() + bounds.y()) * dip_scale_);
   JNIEnv* env = base::android::AttachCurrentThread();
   Java_ViewAndroidDelegate_setViewPosition(
       env, delegate, anchor, bounds.x(), bounds.y(), bounds.width(),
-      bounds.height(), scale, left_margin, top_margin);
+      bounds.height(), dip_scale_, left_margin, top_margin);
 }
 
 ScopedJavaLocalRef<jobject> ViewAndroid::GetContainerView() {
@@ -227,4 +253,30 @@ void ViewAndroid::StartContentIntent(const GURL& content_url,
                                                 is_main_frame);
 }
 
+bool ViewAndroid::OnTouchEvent(const MotionEventAndroid& event,
+                               bool is_touch_handle_event) {
+  if (client_ && client_->OnTouchEvent(event, is_touch_handle_event))

[boliu, 2017/02/27 19:21:57]

what happened to hit testing?

Did that part get reverted too? I mean we still should do hit testing here for
things like touch events, even though it won't actually have any effects until
more refactors..

[boliu, 2017/02/28 03:18:15]

actually, never mind, hit testing can be added later, just pretend everything is
"match parent" for now

[Jinsuk Kim, 2017/02/28 06:56:04]

Done.

[Jinsuk Kim, 2017/02/28 06:56:04]

Restored and saw your comment too late :(
Set |match_parent_ | to true. Take another look and let me know how much you
want to keep or gut out again.

[boliu, 2017/02/28 22:44:54]

Sure :p but bring back the unit tests too :)

[Jinsuk Kim, 2017/03/02 04:08:34]

Done.

+    return true;
+
+  for (auto it = children_.rbegin(); it != children_.rend(); ++it) {
+    if ((*it)->OnTouchEvent(event, is_touch_handle_event))
+      return true;
+  }
+
+  return false;
+}
+
+bool ViewAndroid::OnMouseEvent(const MotionEventAndroid& event,
+                               int action_button) {
+  if (client_ && client_->OnMouseEvent(event, action_button))
+    return true;
+
+  for (auto it = children_.rbegin(); it != children_.rend(); ++it) {
+    if ((*it)->OnMouseEvent(event, action_button))
+      return true;
+  }
+
+  return false;
+}
+
 }  // namespace ui