Implement overscroll support for the virtual keyboard.

content/browser/renderer_host/render_widget_host_view_aura.cc

Index: content/browser/renderer_host/render_widget_host_view_aura.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.cc b/content/browser/renderer_host/render_widget_host_view_aura.cc
index daf80cbdeceb6015c871c26b37ddaedf1161827e..ae56a02ca007134dcb52dabb83b1aa7e93b0a7a4 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -52,6 +52,7 @@
 #include "ui/aura/client/cursor_client_observer.h"
 #include "ui/aura/client/focus_client.h"
 #include "ui/aura/client/screen_position_client.h"
+#include "ui/aura/client/virtual_keyboard_client.h"
 #include "ui/aura/client/window_tree_client.h"
 #include "ui/aura/env.h"
 #include "ui/aura/window.h"
@@ -1715,6 +1716,18 @@ void RenderWidgetHostViewAura::OnSwapCompositorFrame(
                  ack_callback);
 }
 
+float RenderWidgetHostViewAura::GetOverdrawBottomHeight() const {
+  float overdraw = 0.f;
+#if defined(OS_CHROMEOS)
+  gfx::Rect window_bounds = window_->GetBoundsInScreen();
+  gfx::Rect intersect = gfx::IntersectRects(window_bounds,
+                                            virtual_keyboard_bounds_);
+  if (intersect.height() > 0 && intersect.height() < window_bounds.height())
+    overdraw = intersect.height();
+#endif
+  return overdraw;
+}
+
 #if defined(OS_WIN)
 void RenderWidgetHostViewAura::SetParentNativeViewAccessible(
     gfx::NativeViewAccessible accessible_parent) {
@@ -3105,6 +3118,24 @@ void RenderWidgetHostViewAura::OnCursorVisibilityChanged(bool is_visible) {
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+// RenderWidgetHostViewAura, aura::client::VirtualKeyboardObserver
+// implementation:
+
+void RenderWidgetHostViewAura::OnKeyboardBoundsChanging(
+    const gfx::Rect& new_bounds) {
+#if defined(OS_CHROMEOS)
+  aura::client::VirtualKeyboardClient *keyboard_client =
+      aura::client::GetVirtualKeyboardClient(window_->GetRootWindow());
+  if (!keyboard_client || !keyboard_client->IsOverscrollEnabled())
+    return;
+  if (virtual_keyboard_bounds_ != new_bounds) {
+    virtual_keyboard_bounds_ = new_bounds;
+    host_->WasResized();
+  }
+#endif
+}
+
+////////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostViewAura, aura::client::FocusChangeObserver implementation:
 
 void RenderWidgetHostViewAura::OnWindowFocused(aura::Window* gained_focus,
@@ -3520,6 +3551,12 @@ void RenderWidgetHostViewAura::AddedToRootWindow() {
     cursor_client->AddObserver(this);
     NotifyRendererOfCursorVisibilityState(cursor_client->IsCursorVisible());
   }
+
+  aura::client::VirtualKeyboardClient* keyboard_client =
+      aura::client::GetVirtualKeyboardClient(window_->GetRootWindow());
+  if (keyboard_client)
+    keyboard_client->AddObserver(this);
+
   if (current_surface_.get())
     UpdateExternalTexture();
   if (HasFocus()) {
@@ -3550,6 +3587,11 @@ void RenderWidgetHostViewAura::RemovingFromRootWindow() {
   if (cursor_client)
     cursor_client->RemoveObserver(this);
 
+  aura::client::VirtualKeyboardClient* keyboard_client =
+      aura::client::GetVirtualKeyboardClient(window_->GetRootWindow());
+  if (keyboard_client)
+    keyboard_client->RemoveObserver(this);
+
   DetachFromInputMethod();
 
   window_->GetHost()->RemoveObserver(this);