linux_aura: Implement dropping in chrome.

ui/views/widget/desktop_aura/desktop_root_window_host_x11.h

Index: ui/views/widget/desktop_aura/desktop_root_window_host_x11.h
diff --git a/ui/views/widget/desktop_aura/desktop_root_window_host_x11.h b/ui/views/widget/desktop_aura/desktop_root_window_host_x11.h
index e2a936e238332ebf059e4de0e87595091e3a696f..3b7fad59ea4b6b425d7af25df6f9e6ff4ec19574 100644
--- a/ui/views/widget/desktop_aura/desktop_root_window_host_x11.h
+++ b/ui/views/widget/desktop_aura/desktop_root_window_host_x11.h
@@ -15,6 +15,7 @@
 #include "ui/aura/client/cursor_client.h"
 #include "ui/aura/root_window_host.h"
 #include "ui/base/cursor/cursor_loader_x11.h"
+#include "ui/base/dragdrop/desktop_selection_provider_aurax11.h"
 #include "ui/base/x/x11_atom_cache.h"
 #include "ui/gfx/rect.h"
 #include "ui/views/views_export.h"
@@ -30,6 +31,7 @@ class ScreenPositionClient;
 namespace views {
 class DesktopActivationClient;
 class DesktopCaptureClient;
+class DesktopDragDropClientAuraX11;
 class DesktopDispatcherClient;
 class X11DesktopWindowMoveClient;
 class X11WindowEventFilter;
@@ -41,6 +43,7 @@ class CursorManager;
 class VIEWS_EXPORT DesktopRootWindowHostX11
     : public DesktopRootWindowHost,
       public aura::RootWindowHost,
+      public ui::DesktopSelectionProviderAuraX11,
       public MessageLoop::Dispatcher {
  public:
   DesktopRootWindowHostX11(
@@ -171,6 +174,10 @@ class VIEWS_EXPORT DesktopRootWindowHostX11
   virtual void OnDeviceScaleFactorChanged(float device_scale_factor) OVERRIDE;
   virtual void PrepareForShutdown() OVERRIDE;
 
+  // Overridden from DesktopSelectionProviderAuraX11:
+  virtual void SetDropHandler(
+      ui::OSExchangeDataProviderAuraX11* handler) OVERRIDE;
+
   // Overridden from Dispatcher:
   virtual bool Dispatch(const base::NativeEvent& event) OVERRIDE;
 
@@ -208,6 +215,7 @@ class VIEWS_EXPORT DesktopRootWindowHostX11
   scoped_ptr<views::corewm::CursorManager> cursor_client_;
   scoped_ptr<DesktopDispatcherClient> dispatcher_client_;
   scoped_ptr<aura::client::ScreenPositionClient> position_client_;
+  scoped_ptr<DesktopDragDropClientAuraX11> drag_drop_client_;
 
   // Current Aura cursor.
   gfx::NativeCursor current_cursor_;
@@ -224,6 +232,9 @@ class VIEWS_EXPORT DesktopRootWindowHostX11
   aura::RootWindowHostDelegate* root_window_host_delegate_;
   aura::Window* content_window_;
 
+  // We forward drop related messages to this object.
+  ui::OSExchangeDataProviderAuraX11* drop_handler_;
+
   // The current root window host that has capture. While X11 has something
   // like Windows SetCapture()/ReleaseCapture(), it is entirely implicit and
   // there are no notifications when this changes. We need to track this so we