Create a visible window with class name Chrome_RenderWidgetHostHWND which corresponds to the bounds…

content/browser/renderer_host/render_widget_host_view_aura.cc

Index: content/browser/renderer_host/render_widget_host_view_aura.cc
===================================================================
--- content/browser/renderer_host/render_widget_host_view_aura.cc	(revision 248647)
+++ content/browser/renderer_host/render_widget_host_view_aura.cc	(working copy)
@@ -83,6 +83,7 @@
 #include "base/win/windows_version.h"
 #include "content/browser/accessibility/browser_accessibility_manager_win.h"
 #include "content/browser/accessibility/browser_accessibility_win.h"
+#include "content/browser/renderer_host/legacy_render_widget_host_win.h"
 #include "content/common/plugin_constants_win.h"
 #include "ui/base/win/hidden_window.h"
 #include "ui/gfx/gdi_util.h"
@@ -500,7 +501,7 @@
   software_frame_manager_.reset(new SoftwareFrameManager(
       weak_ptr_factory_.GetWeakPtr()));
 #if defined(OS_WIN)
-  plugin_parent_window_ = NULL;
+  legacy_render_widget_host_HWND_ = NULL;
 #endif
   ImageTransportFactory::GetInstance()->AddObserver(this);
 }
@@ -634,11 +635,9 @@
   LPARAM lparam = reinterpret_cast<LPARAM>(this);
   EnumChildWindows(ui::GetHiddenWindow(), ShowWindowsCallback, lparam);
 
-  if (::IsWindow(plugin_parent_window_)) {
-    gfx::Rect window_bounds = window_->GetBoundsInRootWindow();
-    ::SetWindowPos(plugin_parent_window_, NULL, window_bounds.x(),
-                   window_bounds.y(), window_bounds.width(),
-                   window_bounds.height(), 0);
+  if (legacy_render_widget_host_HWND_) {
+    legacy_render_widget_host_HWND_->SetBounds(
+        window_->GetBoundsInRootWindow());
   }
 #endif
 }
@@ -660,8 +659,6 @@
 
     EnumChildWindows(parent, HideWindowsCallback, lparam);
   }
-  if (::IsWindow(plugin_parent_window_))
-    ::SetWindowPos(plugin_parent_window_, NULL, 0, 0, 0, 0, 0);
 #endif
 }
 
@@ -880,11 +877,19 @@
 void RenderWidgetHostViewAura::Show() {
   window_->Show();
   WasShown();
+#if defined(OS_WIN)
+  if (legacy_render_widget_host_HWND_)
+    legacy_render_widget_host_HWND_->Show();
+#endif
 }
 
 void RenderWidgetHostViewAura::Hide() {
   window_->Hide();
   WasHidden();
+#if defined(OS_WIN)
+  if (legacy_render_widget_host_HWND_)
+    legacy_render_widget_host_HWND_->Hide();
+#endif
 }
 
 bool RenderWidgetHostViewAura::IsShowing() {
@@ -1228,27 +1233,24 @@
       selection_focus_rect_);
   }
 #if defined(OS_WIN)
-  // Create the dummy plugin parent window which will be passed as the
-  // container window to windowless plugins.
+  // Create the legacy dummy window which corresponds to the bounds of the
+  // webcontents. This will be passed as the container window for windowless
+  // plugins.
   // Plugins like Flash assume the container window which is returned via the
   // NPNVnetscapeWindow property corresponds to the bounds of the webpage.
   // This is not true in Aura where we have only HWND which is the main Aura
   // window. If we return this window to plugins like Flash then it causes the
   // coordinate translations done by these plugins to break.
-  if (!plugin_parent_window_ && GetNativeViewId()) {
-    plugin_parent_window_ = ::CreateWindowEx(
-        0, L"Static", NULL, WS_CHILDWINDOW, 0, 0, 0, 0,
-        reinterpret_cast<HWND>(GetNativeViewId()), NULL, NULL, NULL);
-    if (::IsWindow(plugin_parent_window_))
-      ::SetProp(plugin_parent_window_, content::kPluginDummyParentProperty,
-                reinterpret_cast<HANDLE>(true));
+  // Additonally the legacy dummy window is needed for accessibility and for
+  // scrolling to work in legacy drivers for trackpoints/trackpads, etc.
+  if (GetNativeViewId()) {
+    if (!legacy_render_widget_host_HWND_) {
+      legacy_render_widget_host_HWND_ = new LegacyRenderWidgetHostHWND(
+          reinterpret_cast<HWND>(GetNativeViewId()));
+    }
+    legacy_render_widget_host_HWND_->SetBounds(
+        window_->GetBoundsInRootWindow());
   }
-  if (::IsWindow(plugin_parent_window_)) {
-    gfx::Rect window_bounds = window_->GetBoundsInRootWindow();
-    ::SetWindowPos(plugin_parent_window_, NULL, window_bounds.x(),
-                   window_bounds.y(), window_bounds.width(),
-                   window_bounds.height(), 0);
-  }
 #endif
 }
 
@@ -1717,7 +1719,11 @@
 
 gfx::NativeViewId RenderWidgetHostViewAura::GetParentForWindowlessPlugin()
     const {
-  return reinterpret_cast<gfx::NativeViewId>(plugin_parent_window_);
+  if (legacy_render_widget_host_HWND_) {
+    return reinterpret_cast<gfx::NativeViewId>(
+        legacy_render_widget_host_HWND_->hwnd());
+  }
+  return NULL;
 }
 #endif
 
@@ -2218,8 +2224,8 @@
   gfx::NativeViewAccessible accessible_parent =
       host_->GetParentNativeViewAccessible();
 
-  BrowserAccessibilityManager* manager = new BrowserAccessibilityManagerWin(
-      hwnd, accessible_parent,
+    BrowserAccessibilityManager* manager = new BrowserAccessibilityManagerWin(
+      legacy_render_widget_host_HWND_, accessible_parent,
       BrowserAccessibilityManagerWin::GetEmptyDocument(), this);
 #else
   BrowserAccessibilityManager* manager = BrowserAccessibilityManager::Create(
@@ -3355,8 +3361,8 @@
   active_frame_subscriber_textures_.clear();
 
 #if defined(OS_WIN)
-  if (::IsWindow(plugin_parent_window_))
-    ::DestroyWindow(plugin_parent_window_);
+  if (legacy_render_widget_host_HWND_)

[sky, 2014/02/05 18:16:47]

nit: no need for if.

[ananta, 2014/02/05 19:52:36]

Code has been changed to call legacy_render_widget_host_HWND_.reset(NULL) as it
is a scoped_ptr

+    delete legacy_render_widget_host_HWND_;
 #endif
 }
 
@@ -3519,6 +3525,14 @@
     if (input_method)
       input_method->SetFocusedTextInputClient(this);
   }
+#if defined(OS_WIN)
+  if (legacy_render_widget_host_HWND_ && GetNativeViewId()) {

[sky, 2014/02/05 18:16:47]

Can you instead destroy in RemoveFromRootWindow and recreate here?

[ananta, 2014/02/05 19:52:36]

I don't think destroying and creating would work given that the same code
executes when a tab is reparented to a new window etc. Plugins request the HWND
once and hold on to it.

[sky, 2014/02/05 21:56:15]

My worry is that I don't know if you are guaranteed a Remove is immediately
followed by an add. If it's not immediate than you've left the
legacy_render_widget_host_HWND_ in the wrong window, and it may end up being
destroyed by virtue of being a child. I think you need to change the parent in
both remove and add.

+    // The parent may have changed here. Ensure that the legacy window is
+    // reparented accordingly.
+    legacy_render_widget_host_HWND_->SetParentWindow(
+        reinterpret_cast<HWND>(GetNativeViewId()));
+  }
+#endif
 }
 
 void RenderWidgetHostViewAura::RemovingFromRootWindow() {