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..773a0242b31f757e2091c7680acff2c7da6b0291 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/event_handler.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 +70,9 @@ 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() : parent_(nullptr),
+                             client_(nullptr),
+                             handler_(nullptr) {}
 
 ViewAndroid::~ViewAndroid() {
   RemoveFromParent();
@@ -86,10 +85,21 @@ 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);
 }
 
+EventHandler* ViewAndroid::GetEventHandler() {
+  if (!parent_ || parent_ == GetWindowAndroid()) {

[boliu, 2016/12/02 23:53:22]

what is the second half of this condition checking? is !parent_ check for root
not enough?

[Jinsuk Kim, 2016/12/05 11:07:44]

In the tree WindowAndroid - ViewAndroid(1) - ViewAndroid(2), I'm adding the
handler in VA(1) not in WA which is the root. Because it won't work for WebView.
VA(1) works for both Chrome and WebView. The second part is actually the
condition that checks if we are VA(1). !parent_ was for sentinel just in case VA
is not linked to WA. I haven't seen it yet though.

[boliu, 2016/12/06 00:10:17]

Ahh I see..

But for chrome (and other non-webview platforms), EventHandler *should* be
created for WindowAndroid.

Also I think GetEventHandler should not be a recursive call. It's more like
"GetOrCreateEventHandlerForThisViewAndroid", which may be illegal and DCHECK if
it violates the above property.

[Jinsuk Kim, 2016/12/06 07:35:07]

Addressed in the new patch.

+    if (!handler_)
+      handler_ = new EventHandler(this);
+    return handler_;
+  }
+  return parent_->GetEventHandler();
+}
+
 void ViewAndroid::AddChild(ViewAndroid* child) {
   DCHECK(child);
   DCHECK(std::find(children_.begin(), children_.end(), child) ==
@@ -179,4 +189,22 @@ bool ViewAndroid::StartDragAndDrop(const JavaRef<jstring>& jtext,
                                                    jimage);
 }
 
+gfx::Size ViewAndroid::GetPhysicalBackingSize() {
+  EventHandler* handler = GetEventHandler();
+  if (!handler)
+    return gfx::Size();
+  return gfx::Size(handler->GetPhysicalBackingSizeWidthPix(),
+                   handler->GetPhysicalBackingSizeHeightPix());
+}
+
+bool ViewAndroid::OnPhysicalBackingSizeChanged(int width, int height) {
+  if (client_ && client_->OnPhysicalBackingSizeChanged(width, height))
+    return true;
+  for (auto it = children_.begin(); it != children_.end(); ++it) {
+    if ((*it)->OnPhysicalBackingSizeChanged(width, height))
+      return true;
+  }
+  return false;
+}
+
 }  // namespace ui