Introduce ViewRoot forwarding 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 96e56495886dd26d8807a5847a0d6f0e12894295..f93d0b6ff08e9dccfb0605de1be1f6a26ad8acd9 100644
--- a/ui/android/view_android.cc
+++ b/ui/android/view_android.cc
@@ -9,7 +9,6 @@
 #include "base/android/jni_android.h"
 #include "cc/layers/layer.h"
 #include "jni/ViewAndroidDelegate_jni.h"
-#include "jni/ViewRoot_jni.h"
 #include "ui/android/view_client.h"
 #include "ui/android/window_android.h"
 #include "ui/display/display.h"
@@ -84,11 +83,6 @@ ViewAndroid::~ViewAndroid() {
     DCHECK_EQ(child->parent_, this);
     child->parent_ = nullptr;
   }
-
-  JNIEnv* env = base::android::AttachCurrentThread();
-  const ScopedJavaLocalRef<jobject> view_root = view_root_.get(env);
-  if (!view_root.is_null())
-    Java_ViewRoot_onDestroyNativeView(env, view_root);
 }
 
 void ViewAndroid::SetDelegate(const JavaRef<jobject>& delegate) {
@@ -110,8 +104,8 @@ void ViewAndroid::AddChild(ViewAndroid* child) {
     child->RemoveFromParent();
   child->parent_ = this;
   if (physical_width_pix_ || physical_height_pix_) {
-    child->OnPhysicalBackingSizeChanged(physical_width_pix_,
-                                        physical_height_pix_);
+    child->OnPhysicalBackingSizeChangedInternal(physical_width_pix_,
+                                                physical_height_pix_);
   }
 }
 
@@ -165,13 +159,13 @@ WindowAndroid* ViewAndroid::GetWindowAndroid() const {
   return parent_ ? parent_->GetWindowAndroid() : nullptr;
 }
 
-ScopedJavaLocalRef<jobject> ViewAndroid::CreateViewRoot() {
-  JNIEnv* env = base::android::AttachCurrentThread();
-  return Java_ViewRoot_create(env, reinterpret_cast<intptr_t>(this));
+void ViewAndroid::SetWindowAndroid(WindowAndroid* window) {
+  DCHECK(parent_) << "The root of this view tree is not present.";
+  parent_->SetWindowAndroid(window);
 }
 
-bool ViewAndroid::HasViewRoot() {
-  return !view_root_.is_uninitialized();
+bool ViewAndroid::IsViewRoot() {
+  return GetViewRoot() == this;
 }
 
 const ScopedJavaLocalRef<jobject> ViewAndroid::GetViewAndroidDelegate()
@@ -193,21 +187,14 @@ void ViewAndroid::SetLayer(scoped_refptr<cc::Layer> layer) {
   UpdateLayerBounds();
 }
 
-ScopedJavaLocalRef<jobject> ViewAndroid::GetViewRoot() {
-  JNIEnv* env = base::android::AttachCurrentThread();
-  const ScopedJavaLocalRef<jobject> view_root = view_root_.get(env);
-  if (!view_root.is_null())
-     return view_root;
-
-  DCHECK(!HasViewRootInTreeHierarchy());
-  view_root_ = JavaObjectWeakGlobalRef(env, CreateViewRoot());
-  return view_root_.get(env);
+ViewAndroid* ViewAndroid::GetViewRoot() {
+  return parent_ ? parent_->GetViewRoot() : nullptr;
 }
 
 bool ViewAndroid::HasViewRootInTreeHierarchy() {

[boliu, 2017/01/03 19:16:11]

I think this linear time check is unnecessary now. The new, more strict
invariant is that ViewRoot is never added as a child of another View. And that's
super easy to enforce in AddChild.

[Jinsuk Kim, 2017/01/04 10:45:02]

Done.

   ViewAndroid* view = parent_;
   while (view) {
-    if (view->HasViewRoot())
+    if (view->IsViewRoot())
       return true;
     view = view->parent_;
   }
@@ -215,7 +202,7 @@ bool ViewAndroid::HasViewRootInTreeHierarchy() {
 }
 
 bool ViewAndroid::HasViewRootInSubtree() {
-  if (HasViewRoot())
+  if (IsViewRoot())
     return true;
   for (auto& child : children_) {
     if (child->HasViewRootInSubtree())
@@ -243,7 +230,7 @@ void ViewAndroid::UpdateLayerBounds() {
     layer_->SetBounds(GetPhysicalBackingSize());
 }
 
-void ViewAndroid::OnPhysicalBackingSizeChanged(int width, int height) {
+void ViewAndroid::OnPhysicalBackingSizeChangedInternal(int width, int height) {
   if (width == physical_width_pix_ && height == physical_height_pix_)
     return;
 
@@ -255,21 +242,6 @@ void ViewAndroid::OnPhysicalBackingSizeChanged(int width, int height) {
     client_->OnPhysicalBackingSizeChanged(width, height);
 
   for (auto& child : children_)
-    child->OnPhysicalBackingSizeChanged(width, height);
+    child->OnPhysicalBackingSizeChangedInternal(width, height);
 }
-
-// static
-void OnPhysicalBackingSizeChanged(JNIEnv* env,
-                                  const JavaParamRef<jclass>& jcaller,
-                                  jlong native_view,
-                                  int width,
-                                  int height) {
-  ViewAndroid* view_android = reinterpret_cast<ViewAndroid*>(native_view);
-  view_android->OnPhysicalBackingSizeChanged(width, height);
-}
-
-bool RegisterViewRoot(JNIEnv* env) {
-  return RegisterNativesImpl(env);
-}
-
 }  // namespace ui