Disable VK overscroll for login/out-of-box.

ui/keyboard/keyboard_util.cc

Index: ui/keyboard/keyboard_util.cc
diff --git a/ui/keyboard/keyboard_util.cc b/ui/keyboard/keyboard_util.cc
index e28f6d00fb95851203f9803a4dc777b5d3132a81..9c89e6442b3a4ca5119511cfff249e1b63fdb3f1 100644
--- a/ui/keyboard/keyboard_util.cc
+++ b/ui/keyboard/keyboard_util.cc
@@ -44,6 +44,9 @@ base::LazyInstance<GURL> g_override_content_url = LAZY_INSTANCE_INITIALIZER;
 
 bool g_touch_keyboard_enabled = false;
 
+keyboard::KeyboardOverscrolOverride g_keyboard_overscroll_override =
+    keyboard::KEYBOARD_OVERSCROLL_OVERRIDE_NONE;
+
 }  // namespace
 
 namespace keyboard {
@@ -109,10 +112,19 @@ bool IsKeyboardUsabilityExperimentEnabled() {
 bool IsKeyboardOverscrollEnabled() {
   if (!IsKeyboardEnabled())
     return false;
+
   // Users of the accessibility on-screen keyboard are likely to be using mouse
   // input, which may interfere with overscrolling.
   if (g_accessibility_keyboard_enabled)
     return false;
+
+  // If overscroll enabled override is set, use it instead. Currently
+  // login / out-of-box disable keyboard overscroll. http://crbug.com/363635
+  if (g_keyboard_overscroll_override != KEYBOARD_OVERSCROLL_OVERRIDE_NONE) {
+    return g_keyboard_overscroll_override ==
+        KEYBOARD_OVERSCROLL_OVERRIDE_ENABLED;
+  }
+
   if (CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kDisableVirtualKeyboardOverscroll)) {
     return false;
@@ -120,6 +132,10 @@ bool IsKeyboardOverscrollEnabled() {
   return true;
 }
 
+void SetKeyboardOverscrollOverride(KeyboardOverscrolOverride override) {
+  g_keyboard_overscroll_override = override;
+}
+
 bool IsInputViewEnabled() {
   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnableInputView))
     return true;