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..9bb8c2cce741088fde672d0df302a7defafca606 100644
--- a/ui/android/view_android.cc
+++ b/ui/android/view_android.cc
@@ -8,13 +8,16 @@
 
 #include "base/android/jni_android.h"
 #include "cc/layers/layer.h"
+#include "jni/EventHandler_jni.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;
 
@@ -68,24 +71,29 @@ 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) {}
+ViewAndroid::ViewAndroid() : ViewAndroid(nullptr) {}
 
 ViewAndroid::~ViewAndroid() {
   RemoveFromParent();
 
-  for (std::list<ViewAndroid*>::iterator it = children_.begin();
-       it != children_.end(); it++) {
-    DCHECK_EQ((*it)->parent_, this);
-    (*it)->parent_ = nullptr;
+  for (auto& child : children_) {
+    DCHECK_EQ(child->parent_, this);
+    child->parent_ = nullptr;
   }
+
+  JNIEnv* env = base::android::AttachCurrentThread();
+  const ScopedJavaLocalRef<jobject> handler = event_handler_.get(env);
+  if (!handler.is_null())
+    Java_EventHandler_onDestroyNativeView(env, handler);
 }
 
 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);
 }
@@ -94,11 +102,17 @@ 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_)
     child->RemoveFromParent();
   child->parent_ = this;
+  if (physical_width_pix_ || physical_height_pix_) {
+    child->OnPhysicalBackingSizeChanged(physical_width_pix_,
+                                        physical_height_pix_);
+  }
 }
 
 void ViewAndroid::RemoveFromParent() {
@@ -151,6 +165,15 @@ WindowAndroid* ViewAndroid::GetWindowAndroid() const {
   return parent_ ? parent_->GetWindowAndroid() : nullptr;
 }
 
+ScopedJavaLocalRef<jobject> ViewAndroid::CreateEventHandler() {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  return Java_EventHandler_create(env, reinterpret_cast<intptr_t>(this));
+}
+
+bool ViewAndroid::HasEventHandler() {
+  return !event_handler_.is_uninitialized();
+}
+
 const ScopedJavaLocalRef<jobject> ViewAndroid::GetViewAndroidDelegate()
     const {
   JNIEnv* env = base::android::AttachCurrentThread();
@@ -167,6 +190,38 @@ cc::Layer* ViewAndroid::GetLayer() const {
 
 void ViewAndroid::SetLayer(scoped_refptr<cc::Layer> layer) {
   layer_ = layer;
+  UpdateLayerBounds();
+}
+
+ScopedJavaLocalRef<jobject> ViewAndroid::GetEventHandler() {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  const ScopedJavaLocalRef<jobject> handler = event_handler_.get(env);
+  if (!handler.is_null())
+    return handler;
+
+  DCHECK(!HasEventHandlerInTreeHierarchy());
+  event_handler_ = JavaObjectWeakGlobalRef(env, CreateEventHandler());
+  return event_handler_.get(env);
+}
+
+bool ViewAndroid::HasEventHandlerInTreeHierarchy() {
+  ViewAndroid* view = parent_;
+  while (view) {
+    if (view->HasEventHandler())
+      return true;
+    view = view->parent_;
+  }
+  return HasEventHandlerInSubtree();
+}
+
+bool ViewAndroid::HasEventHandlerInSubtree() {
+  if (HasEventHandler())
+    return true;
+  for (auto& child : children_) {
+    if (child->HasEventHandlerInSubtree())
+      return true;
+  }
+  return false;
 }
 
 bool ViewAndroid::StartDragAndDrop(const JavaRef<jstring>& jtext,
@@ -179,4 +234,42 @@ bool ViewAndroid::StartDragAndDrop(const JavaRef<jstring>& jtext,
                                                    jimage);
 }
 
+gfx::Size ViewAndroid::GetPhysicalBackingSize() {
+  return gfx::Size(physical_width_pix_, physical_height_pix_);
+}
+
+void ViewAndroid::UpdateLayerBounds() {
+  if (layer_)
+    layer_->SetBounds(GetPhysicalBackingSize());
+}
+
+void ViewAndroid::OnPhysicalBackingSizeChanged(int width, int height) {
+  if (width == physical_width_pix_ && height == physical_height_pix_)
+    return;
+
+  physical_width_pix_ = width;
+  physical_height_pix_ = height;
+  UpdateLayerBounds();
+
+  if (client_)
+    client_->OnPhysicalBackingSizeChanged(width, height);
+
+  for (auto& child : children_)
+    child->OnPhysicalBackingSizeChanged(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 RegisterEventHandler(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
 }  // namespace ui