Remove fullscreen handwriting flag when deciding to update insets.

Currently, when windows change bounds with the virtual keyboard open,
we update their insets (visual viewport size), because the overlap
between the window and the virtual keyboard has changed.

A previous CL added a check so that if the fullscreen handwriting flag
is enabled, we don't update the insets. The intention was to reset
the inset if we are using fullscreen handwriting mode, but the
code actually checked if fullscreen handwriting mode was enabled.
This meant that we would stop updating insets if the fullscreen
handwriting flag was on, even if we are not using fullscreen
handwriting.

This patch removes this check. The insets are updated by occluded
bounds and fullscreen handwriting has empty occluded bounds (for now),
so we don't introduce any problems.

TBR=yhanada@chromium.org

Change-Id: I4285fb6fc4bcc50fcf502ca6c9c439c8d2aef97f
Reviewed-on: https://chromium-review.googlesource.com/1154780Reviewed-by: Darren Shen <shend@chromium.org>
Reviewed-by: Yuichiro Hanada <yhanada@chromium.org>
Commit-Queue: Darren Shen <shend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579222}

chrome/browser/ui/ash/chrome_keyboard_ui.cc

@@ -479,8 +479,7 @@ bool ChromeKeyboardUI::ShouldEnableInsets(aura::Window* window) {
   return (contents_window->GetRootWindow() == window->GetRootWindow() &&
           keyboard::IsKeyboardOverscrollEnabled() &&
           contents_window->IsVisible() &&
-          keyboard_controller()->IsKeyboardVisible() &&
-          !keyboard::IsFullscreenHandwritingVirtualKeyboardEnabled());
+          keyboard_controller()->IsKeyboardVisible());
 }
 
 void ChromeKeyboardUI::AddBoundsChangedObserver(aura::Window* window) {