Introduce ViewRoot forwarding input/view events to native

ui/snapshot/snapshot_android.cc

Index: ui/snapshot/snapshot_android.cc
diff --git a/ui/snapshot/snapshot_android.cc b/ui/snapshot/snapshot_android.cc
index 557a325db03b1682b79613561520a3070ea4bfb0..4feb0b13e108a97e845fc929283b55a0872a4f03 100644
--- a/ui/snapshot/snapshot_android.cc
+++ b/ui/snapshot/snapshot_android.cc
@@ -10,6 +10,7 @@
 #include "base/bind.h"
 #include "cc/output/copy_output_request.h"
 #include "third_party/skia/include/core/SkBitmap.h"
+#include "ui/android/display_android_manager.h"
 #include "ui/android/view_android.h"
 #include "ui/android/window_android.h"
 #include "ui/android/window_android_compositor.h"
@@ -42,8 +43,10 @@ static void MakeAsyncCopyRequest(
   std::unique_ptr<cc::CopyOutputRequest> request =
       cc::CopyOutputRequest::CreateBitmapRequest(callback);
 
+  DisplayAndroidManager* display_manager =
+      static_cast<DisplayAndroidManager*>(display::Screen::GetScreen());

[boliu, 2017/01/04 18:58:06]

cast should happen in DisplayAndroidManager, maybe should just have a
DisplayAndroidManager::GetInstance?

[Jinsuk Kim, 2017/01/05 11:03:13]

Done.

   const display::Display& display =
-      display::Screen::GetScreen()->GetDisplayNearestWindow(window);
+      display_manager->GetDisplayNearestWindowAndroid(window);
   float device_scale_factor = display.device_scale_factor();
   gfx::Rect source_rect_in_pixel =
       gfx::ScaleToEnclosingRect(source_rect, device_scale_factor);