Resize only the virtual viewport when the OSK triggers a resize.

content/browser/renderer_host/render_widget_host_view_android.cc

Index: content/browser/renderer_host/render_widget_host_view_android.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_android.cc b/content/browser/renderer_host/render_widget_host_view_android.cc
index 65ed654f0342d396762742fb6e6c2c96cb3bd857..c73301d7d75ab9e9edf14e687b67a62fc188d724 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -615,9 +615,20 @@ gfx::Rect RenderWidgetHostViewAndroid::GetViewBounds() const {
   if (!content_view_core_)
     return gfx::Rect(default_size_);
 
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableOSKOverscroll))
+    return gfx::Rect(content_view_core_->GetViewSizeWithOSKHidden());
+
   return gfx::Rect(content_view_core_->GetViewSize());
 }
 
+gfx::Size RenderWidgetHostViewAndroid::GetVisibleViewportSize() const {
+  if (!content_view_core_)
+    return gfx::Rect(default_size_).size();
+
+  return gfx::Rect(content_view_core_->GetViewSize()).size();
+}
+
 gfx::Size RenderWidgetHostViewAndroid::GetPhysicalBackingSize() const {
   if (!content_view_core_)
     return gfx::Size();