Work on getting things built with -Wimplicit-fallthrough. This CL was uploaded by git cl split.

Bug: 177475
R=sky@chromium.org

Change-Id: I50a90b6d627f831e31819abca4494c1b2d54600d
Reviewed-on: https://chromium-review.googlesource.com/889844
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532139}

ui/aura/env_input_state_controller.cc

@@ -47,7 +47,7 @@ void EnvInputStateController::UpdateStateForTouchEvent(
     case ui::ET_TOUCH_CANCELLED:
       if (!event.HasNativeEvent())
         break;
-    // fallthrough
+      FALLTHROUGH;
     case ui::ET_TOUCH_RELEASED:
       touch_ids_down_ = (touch_ids_down_ | (1 << event.pointer_details().id)) ^
                         (1 << event.pointer_details().id);

ui/aura/mus/system_input_injector_mus.cc

@@ -76,6 +76,7 @@ void SystemInputInjectorMus::InjectMouseButton(ui::EventFlags button,
       break;
     case ui::EF_MIDDLE_MOUSE_BUTTON:
       modifier = ui::MODIFIER_MIDDLE_MOUSE_BUTTON;
+      break;
     default:
       LOG(WARNING) << "Invalid flag: " << button << " for the button parameter";
       return;

ui/aura/test/test_window_delegate.cc

@@ -163,6 +163,7 @@ void EventCountDelegate::OnKeyEvent(ui::KeyEvent* event) {
       break;
     case ui::ET_KEY_RELEASED:
       key_release_count_++;
+      break;
     default:
       break;
   }

ui/aura/test/x11_event_sender.cc

@@ -36,6 +36,7 @@ void PostEventToWindowTreeHost(const XEvent& xevent, WindowTreeHost* host) {
       host->ConvertDIPToScreenInPixels(&point);
       event.xmotion.x_root = point.x();
       event.xmotion.y_root = point.y();
+      break;
     }
     default:
       break;