Introduce ViewRoot to forward input/view events to native

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 664758cd5304088709f1cd99bdb655bae764aadf..e88b9b008d8e71aa844972999ac575daa78c199b 100644
--- a/ui/android/view_android.cc
+++ b/ui/android/view_android.cc
@@ -9,12 +9,14 @@
 #include "base/android/jni_android.h"
 #include "cc/layers/layer.h"
 #include "jni/ViewAndroidDelegate_jni.h"
+#include "ui/android/view_client.h"
 #include "ui/android/window_android.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
 
 namespace ui {
 
+using base::android::JavaParamRef;
 using base::android::JavaRef;
 using base::android::ScopedJavaLocalRef;
 
@@ -68,12 +70,12 @@ ViewAndroid::ScopedAnchorView::view() const {
   return view_.get(env);
 }
 
-ViewAndroid::ViewAndroid(const JavaRef<jobject>& delegate)
-    : parent_(nullptr)
-    , delegate_(base::android::AttachCurrentThread(),
-                delegate.obj()) {}
-
-ViewAndroid::ViewAndroid() : parent_(nullptr) {}
+ViewAndroid::ViewAndroid(ViewClient* client) : parent_(nullptr),
+                                               client_(client),
+                                               physical_width_pix_(0),
+                                               physical_height_pix_(0),
+                                               has_event_handler_(false) {}
+ViewAndroid::ViewAndroid() : ViewAndroid(nullptr) {}
 
 ViewAndroid::~ViewAndroid() {
   RemoveFromParent();
@@ -86,6 +88,8 @@ 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);
 }
@@ -94,6 +98,8 @@ void ViewAndroid::AddChild(ViewAndroid* child) {
   DCHECK(child);
   DCHECK(std::find(children_.begin(), children_.end(), child) ==
          children_.end());
+  DCHECK(!HasEventHandlerInTreeHierarchy() ||
+         !child->HasEventHandlerInSubtree());
 
   children_.push_back(child);
   if (child->parent_)
@@ -169,6 +175,31 @@ void ViewAndroid::SetLayer(scoped_refptr<cc::Layer> layer) {
   layer_ = layer;
 }
 
+void ViewAndroid::OnSetEventHandler() {
+  DCHECK(!HasEventHandlerInTreeHierarchy());
+  has_event_handler_ = true;
+}
+
+bool ViewAndroid::HasEventHandlerInTreeHierarchy() {
+  ViewAndroid* view = parent_;
+  while (view) {
+    if (view->has_event_handler())
+      return true;
+    view = view->parent_;
+  }
+  return HasEventHandlerInSubtree();
+}
+
+bool ViewAndroid::HasEventHandlerInSubtree() {
+  if (has_event_handler_)
+    return true;
+  for (auto it = children_.begin(); it != children_.end(); ++it) {

[boliu, 2016/12/06 23:15:46]

style: you can use for-each style "for (auto& child : children_)"

[Jinsuk Kim, 2016/12/07 12:36:28]

Done.

+    if ((*it)->HasEventHandlerInSubtree())
+      return true;
+  }
+  return false;
+}
+
 bool ViewAndroid::StartDragAndDrop(const JavaRef<jstring>& jtext,
                                    const JavaRef<jobject>& jimage) {
   ScopedJavaLocalRef<jobject> delegate(GetViewAndroidDelegate());
@@ -179,4 +210,30 @@ bool ViewAndroid::StartDragAndDrop(const JavaRef<jstring>& jtext,
                                                    jimage);
 }
 
+gfx::Size ViewAndroid::GetPhysicalBackingSize() {
+  return gfx::Size(physical_width_pix_, physical_height_pix_);
+}
+
+void ViewAndroid::SetPhysicalBackingSize(int width, int height) {

[boliu, 2016/12/06 23:15:46]

nit: maybe this can just be inlined, a bit confusing to have both this and
OnPhysicalBackingSizeChanged

[Jinsuk Kim, 2016/12/07 12:36:28]

Done.

+  physical_width_pix_ = width;
+  physical_height_pix_ = height;
+  UpdateLayerBounds();
+}
+
+void ViewAndroid::UpdateLayerBounds() {
+  layer_->SetBounds(GetPhysicalBackingSize());
+}
+
+void ViewAndroid::OnPhysicalBackingSizeChanged(int width, int height) {
+  if (width == physical_width_pix_ && height == physical_height_pix_)
+    return;
+
+  SetPhysicalBackingSize(width, height);
+  if (client_)
+    client_->OnPhysicalBackingSizeChanged(width, height);
+
+  for (auto it = children_.begin(); it != children_.end(); ++it)

[boliu, 2016/12/06 23:15:46]

ditto for-each loop

[Jinsuk Kim, 2016/12/07 12:36:28]

Done.

+    (*it)->OnPhysicalBackingSizeChanged(width, height);
+}
+
 }  // namespace ui