Disable screen rotation when splitview is engaged and only allow splitview in landscape.

athena/wm/split_view_controller.cc

Index: athena/wm/split_view_controller.cc
diff --git a/athena/wm/split_view_controller.cc b/athena/wm/split_view_controller.cc
index 3c019d4608d98794a569a8f9e0a8d7d7a6f28898..43984d7389051b6d35945226d7c9b7bf40bc04f1 100644
--- a/athena/wm/split_view_controller.cc
+++ b/athena/wm/split_view_controller.cc
@@ -6,6 +6,7 @@
 
 #include <cmath>
 
+#include "athena/screen/public/screen_manager.h"
 #include "athena/wm/public/window_list_provider.h"
 #include "athena/wm/public/window_manager.h"
 #include "base/bind.h"
@@ -33,6 +34,11 @@ gfx::Transform GetTargetTransformForBoundsAnimation(const gfx::Rect& from,
   return transform;
 }
 
+bool IsLandscapeOrientation(gfx::Display::Rotation rotation) {
+  return rotation == gfx::Display::ROTATE_0 ||
+         rotation == gfx::Display::ROTATE_180;
+}
+
 }  // namespace
 
 SplitViewController::SplitViewController(
@@ -127,6 +133,7 @@ void SplitViewController::DeactivateSplitMode() {
   state_ = INACTIVE;
   UpdateLayout(false);
   left_window_ = right_window_ = NULL;
+  ScreenManager::Get()->SetRotationLocked(false);
 }
 
 gfx::Rect SplitViewController::GetLeftTargetBounds() {
@@ -147,6 +154,10 @@ void SplitViewController::UpdateLayout(bool animate) {
   CHECK(left_window_);
   CHECK(right_window_);
 
+  // Splitview can be activated from SplitViewController::ActivateSplitMode or
+  // SplitViewController::ScrollEnd. Additionally we don't want to rotate the
+  // screen while engaging splitview (i.e. state_ == SCROLLING).
+  ScreenManager::Get()->SetRotationLocked(state_ != INACTIVE);

[mfomitchev, 2014/09/03 15:33:59]

Perhaps we should create a SetState() method and lock/unlock rotation there.
This way the logic would be centralized and we won't be calling
SetRotationLocked when we don't need to.

[flackr, 2014/09/03 16:42:13]

Done.

   if (state_ == INACTIVE && !animate) {
     if (!wm::IsActiveWindow(left_window_))
       left_window_->Hide();
@@ -293,9 +304,11 @@ void SplitViewController::ScrollUpdate(float delta) {
 }
 
 bool SplitViewController::CanScroll() {
-  // TODO(mfomitchev): return false in vertical orientation, in full screen.
+  // TODO(mfomitchev): return false in full screen.
   bool result = (!IsSplitViewModeActive() &&
-                 window_list_provider_->GetWindowList().size() >= 2);
+                 window_list_provider_->GetWindowList().size() >= 2 &&
+                 IsLandscapeOrientation(gfx::Screen::GetNativeScreen()->
+                     GetDisplayNearestWindow(container_).rotation()));
   return result;
 }