Refactor EventHandler out of RenderWidgetHostViewAura

content/browser/renderer_host/render_widget_host_view_event_handler.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/renderer_host/render_widget_host_view_event_handler.h"
+
+#include "base/metrics/user_metrics_action.h"
+#include "content/browser/renderer_host/input/touch_selection_controller_client_aura.h"
+#include "content/browser/renderer_host/overscroll_controller.h"
+#include "content/browser/renderer_host/render_view_host_delegate.h"
+#include "content/browser/renderer_host/render_view_host_delegate_view.h"
+#include "content/browser/renderer_host/render_widget_host_impl.h"
+#include "content/browser/renderer_host/render_widget_host_input_event_router.h"
+#include "content/browser/renderer_host/render_widget_host_view_base.h"
+#include "content/browser/renderer_host/text_input_manager.h"
+#include "content/common/content_switches_internal.h"
+#include "content/common/site_isolation_policy.h"
+#include "content/public/browser/render_view_host.h"
+#include "content/public/browser/render_widget_host.h"
+#include "content/public/browser/user_metrics.h"
+#include "ui/aura/client/cursor_client.h"
+#include "ui/aura/client/focus_client.h"
+#include "ui/aura/client/screen_position_client.h"
+#include "ui/aura/window.h"
+#include "ui/aura/window_delegate.h"
+#include "ui/base/ime/text_input_client.h"
+#include "ui/events/blink/blink_event_util.h"
+#include "ui/events/blink/web_input_event.h"
+#include "ui/touch_selection/touch_selection_controller.h"
+
+#if defined(OS_WIN)
+#include "content/browser/frame_host/render_frame_host_impl.h"
+#include "content/public/common/context_menu_params.h"
+#include "ui/aura/window_tree_host.h"
+#include "ui/display/screen.h"
+#endif  // defined(OS_WIN)
+
+namespace {
+
+// In mouse lock mode, we need to prevent the (invisible) cursor from hitting
+// the border of the view, in order to get valid movement information. However,
+// forcing the cursor back to the center of the view after each mouse move
+// doesn't work well. It reduces the frequency of useful mouse move messages
+// significantly. Therefore, we move the cursor to the center of the view only
+// if it approaches the border. |kMouseLockBorderPercentage| specifies the width
+// of the border area, in percentage of the corresponding dimension.
+const int kMouseLockBorderPercentage = 15;

[tdresser, 2016/09/23 13:54:09]

I am sad that this review forced me to learn that this exists...

[jonross, 2016/10/05 15:37:57]

:( same

+
+#if defined(OS_WIN)

[tdresser, 2016/09/23 13:54:09]

Not in this patch, but I wonder how hard it would be to make a
RenderWidgetHostAuraEventHandlerWin subclass...

Might be worth filing a Hotlist-InputDev bug.

[jonross, 2016/10/05 15:44:17]

crbug.com/653126 filed

+// A callback function for EnumThreadWindows to enumerate and dismiss
+// any owned popup windows.
+BOOL CALLBACK DismissOwnedPopups(HWND window, LPARAM arg) {
+  const HWND toplevel_hwnd = reinterpret_cast<HWND>(arg);
+
+  if (::IsWindowVisible(window)) {
+    const HWND owner = ::GetWindow(window, GW_OWNER);
+    if (toplevel_hwnd == owner) {
+      ::PostMessage(window, WM_CANCELMODE, 0, 0);
+    }
+  }
+
+  return TRUE;
+}
+#endif  // defined(OS_WIN)
+
+gfx::Point GetScreenLocationFromEvent(const ui::LocatedEvent& event) {
+  aura::Window* root =
+      static_cast<aura::Window*>(event.target())->GetRootWindow();
+  aura::client::ScreenPositionClient* spc =
+      aura::client::GetScreenPositionClient(root);
+  if (!spc)
+    return event.root_location();
+
+  gfx::Point screen_location(event.root_location());
+  spc->ConvertPointToScreen(root, &screen_location);
+  return screen_location;
+}
+
+bool IsFractionalScaleFactor(float scale_factor) {
+  return (scale_factor - static_cast<int>(scale_factor)) > 0;
+}
+
+// We don't mark these as handled so that they're sent back to the
+// DefWindowProc so it can generate WM_APPCOMMAND as necessary.
+bool IsXButtonUpEvent(const ui::MouseEvent* event) {
+#if defined(OS_WIN)
+  switch (event->native_event().message) {
+    case WM_XBUTTONUP:
+    case WM_NCXBUTTONUP:
+      return true;
+  }
+#endif
+  return false;
+}
+
+// Reset unchanged touch point to StateStationary for touchmove and

[tdresser, 2016/09/23 13:54:09]

point -> points

[jonross, 2016/10/05 15:37:57]

Done.

+// touchcancel.
+void MarkUnchangedTouchPointsAsStationary(blink::WebTouchEvent* event,
+                                          int changed_touch_id) {
+  if (event->type == blink::WebInputEvent::TouchMove ||
+      event->type == blink::WebInputEvent::TouchCancel) {
+    for (size_t i = 0; i < event->touchesLength; ++i) {
+      if (event->touches[i].id != changed_touch_id)
+        event->touches[i].state = blink::WebTouchPoint::StateStationary;
+    }
+  }
+}
+
+bool NeedsInputGrab(content::RenderWidgetHostViewBase* view) {
+  if (!view)
+    return false;
+  return view->GetPopupType() == blink::WebPopupTypePage;
+}
+
+}  // namespace
+
+namespace content {
+
+RenderWidgetHostViewEventHandler::Delegate::Delegate()
+    : selection_controller_client_(nullptr),
+      selection_controller_(nullptr),
+      overscroll_controller_(nullptr) {}
+
+RenderWidgetHostViewEventHandler::Delegate::~Delegate() {}
+
+RenderWidgetHostViewEventHandler::RenderWidgetHostViewEventHandler(
+    RenderWidgetHostImpl* host,
+    RenderWidgetHostViewBase* host_view,
+    Delegate* delegate)
+    : accept_return_character_(false),
+      disable_input_event_router_for_testing_(false),
+      mouse_locked_(false),
+      pinch_zoom_enabled_(content::IsPinchToZoomEnabled()),
+      set_focus_on_mouse_down_or_key_event_(false),
+      synthetic_move_sent_(false),
+      host_(RenderWidgetHostImpl::From(host)),
+      host_view_(host_view),
+      popup_child_host_view_(nullptr),
+      popup_child_event_handler_(nullptr),
+      delegate_(delegate),
+      window_(nullptr) {}
+
+RenderWidgetHostViewEventHandler::~RenderWidgetHostViewEventHandler() {}
+
+void RenderWidgetHostViewEventHandler::SetPopupChild(
+    RenderWidgetHostViewBase* popup_child_host_view,
+    ui::EventHandler* popup_child_event_handler) {
+  popup_child_host_view_ = popup_child_host_view;
+  popup_child_event_handler_ = popup_child_event_handler;
+}
+
+void RenderWidgetHostViewEventHandler::TrackHost(
+    aura::Window* reference_window) {
+  if (!reference_window)
+    return;
+  host_tracker_.reset(new aura::WindowTracker);
+  host_tracker_->Add(reference_window);
+}
+
+#if defined(OS_WIN)
+void RenderWidgetHostViewEventHandler::SetContextMenuParams(
+    const ContextMenuParams& params) {
+  last_context_menu_params_.reset();
+  if (params.source_type == ui::MENU_SOURCE_LONG_PRESS) {
+    last_context_menu_params_.reset(new ContextMenuParams);
+    *last_context_menu_params_ = params;
+  }
+}
+
+void RenderWidgetHostViewEventHandler::UpdateMouseLockRegion() {
+  RECT window_rect =
+      display::Screen::GetScreen()
+          ->DIPToScreenRectInWindow(window_, window_->GetBoundsInScreen())
+          .ToRECT();
+  ::ClipCursor(&window_rect);
+}
+#endif
+
+bool RenderWidgetHostViewEventHandler::LockMouse() {
+  aura::Window* root_window = window_->GetRootWindow();
+  if (!root_window)
+    return false;
+
+  if (mouse_locked_)
+    return true;
+
+  mouse_locked_ = true;
+#if !defined(OS_WIN)
+  window_->SetCapture();
+#else
+  UpdateMouseLockRegion();
+#endif
+  aura::client::CursorClient* cursor_client =
+      aura::client::GetCursorClient(root_window);
+  if (cursor_client) {
+    cursor_client->HideCursor();
+    cursor_client->LockCursor();
+  }
+
+  if (ShouldMoveToCenter()) {
+    synthetic_move_sent_ = true;
+    window_->MoveCursorTo(gfx::Rect(window_->bounds().size()).CenterPoint());
+  }
+  delegate_->SetTooltipsEnabled(false);
+  return true;
+}
+
+void RenderWidgetHostViewEventHandler::UnlockMouse() {
+  delegate_->SetTooltipsEnabled(true);
+
+  aura::Window* root_window = window_->GetRootWindow();
+  if (!mouse_locked_ || !root_window)
+    return;
+
+  mouse_locked_ = false;
+
+  if (window_->HasCapture())
+    window_->ReleaseCapture();
+
+#if defined(OS_WIN)
+  ::ClipCursor(NULL);
+#endif
+
+  // Ensure that the global mouse position is updated here to its original
+  // value. If we don't do this then the synthesized mouse move which is posted
+  // after the cursor is moved ends up getting a large movement delta which is
+  // not what sites expect. The delta is computed in the
+  // ModifyEventMovementAndCoords function.
+  global_mouse_position_ = unlocked_global_mouse_position_;
+  window_->MoveCursorTo(unlocked_mouse_position_);
+
+  aura::client::CursorClient* cursor_client =
+      aura::client::GetCursorClient(root_window);
+  if (cursor_client) {
+    cursor_client->UnlockCursor();
+    cursor_client->ShowCursor();
+  }
+  host_->LostMouseLock();
+}
+
+void RenderWidgetHostViewEventHandler::OnKeyEvent(ui::KeyEvent* event) {
+  TRACE_EVENT0("input", "RenderWidgetHostViewBase::OnKeyEvent");
+
+  if (NeedsInputGrab(popup_child_host_view_)) {
+    popup_child_event_handler_->OnKeyEvent(event);
+    if (event->handled())
+      return;
+  }
+
+  // We need to handle the Escape key for Pepper Flash.
+  if (host_view_->is_fullscreen() && event->key_code() == ui::VKEY_ESCAPE) {
+    // Focus the window we were created from.
+    if (host_tracker_.get() && !host_tracker_->windows().empty()) {
+      aura::Window* host = *(host_tracker_->windows().begin());
+      aura::client::FocusClient* client = aura::client::GetFocusClient(host);
+      if (client) {
+        // Calling host->Focus() may delete |this|. We create a local observer
+        // for that. In that case we exit without further access to any members.
+        aura::WindowTracker tracker;
+        aura::Window* window = window_;
+        tracker.Add(window);
+        host->Focus();
+        if (!tracker.Contains(window)) {
+          event->SetHandled();
+          return;
+        }
+      }
+    }
+    delegate_->Shutdown();
+  } else {
+    if (event->key_code() == ui::VKEY_RETURN) {
+      // Do not forward return key release events if no press event was handled.
+      if (event->type() == ui::ET_KEY_RELEASED && !accept_return_character_)
+        return;
+      // Accept return key character events between press and release events.
+      accept_return_character_ = event->type() == ui::ET_KEY_PRESSED;
+    }
+
+    // Call SetKeyboardFocus() for not only ET_KEY_PRESSED but also
+    // ET_KEY_RELEASED. If a user closed the hotdog menu with ESC key press,
+    // we need to notify focus to Blink on ET_KEY_RELEASED for ESC key.
+    SetKeyboardFocus();
+    // We don't have to communicate with an input method here.
+    NativeWebKeyboardEvent webkit_event(*event);
+    delegate_->ForwardKeyboardEvent(webkit_event);
+  }
+  event->SetHandled();
+}
+
+void RenderWidgetHostViewEventHandler::OnMouseEvent(ui::MouseEvent* event) {
+  TRACE_EVENT0("input", "RenderWidgetHostViewBase::OnMouseEvent");
+  ForwardMouseEventToParent(event);
+  // TODO(mgiuca): Return if event->handled() returns true. This currently
+  // breaks drop-down lists which means something is incorrectly setting
+  // event->handled to true (http://crbug.com/577983).
+
+  if (mouse_locked_) {
+    HandleMouseEventWhileLocked(event);
+    return;
+  }
+
+  // As the overscroll is handled during scroll events from the trackpad, the
+  // RWHVA window is transformed by the overscroll controller. This transform
+  // triggers a synthetic mouse-move event to be generated (by the aura
+  // RootWindow). But this event interferes with the overscroll gesture. So,
+  // ignore such synthetic mouse-move events if an overscroll gesture is in
+  // progress.
+  OverscrollController* overscroll_controller =
+      delegate_->overscroll_controller();
+  if (overscroll_controller &&
+      overscroll_controller->overscroll_mode() != OVERSCROLL_NONE &&
+      event->flags() & ui::EF_IS_SYNTHESIZED &&
+      (event->type() == ui::ET_MOUSE_ENTERED ||
+       event->type() == ui::ET_MOUSE_EXITED ||
+       event->type() == ui::ET_MOUSE_MOVED)) {
+    event->StopPropagation();
+    return;
+  }
+
+  if (event->type() == ui::ET_MOUSEWHEEL) {
+#if defined(OS_WIN)
+    // We get mouse wheel/scroll messages even if we are not in the foreground.
+    // So here we check if we have any owned popup windows in the foreground and
+    // dismiss them.
+    aura::WindowTreeHost* host = window_->GetHost();
+    if (host) {
+      HWND parent = host->GetAcceleratedWidget();
+      HWND toplevel_hwnd = ::GetAncestor(parent, GA_ROOT);
+      EnumThreadWindows(GetCurrentThreadId(), DismissOwnedPopups,
+                        reinterpret_cast<LPARAM>(toplevel_hwnd));
+    }
+#endif
+    blink::WebMouseWheelEvent mouse_wheel_event =
+        ui::MakeWebMouseWheelEvent(static_cast<ui::MouseWheelEvent&>(*event),
+                                   base::Bind(&GetScreenLocationFromEvent));
+    if (mouse_wheel_event.deltaX != 0 || mouse_wheel_event.deltaY != 0) {
+      if (ShouldRouteEvent(event)) {
+        host_->delegate()->GetInputEventRouter()->RouteMouseWheelEvent(
+            host_view_, &mouse_wheel_event);
+      } else {
+        ProcessMouseWheelEvent(mouse_wheel_event, *event->latency());
+      }
+    }
+  } else {
+    bool is_selection_popup = NeedsInputGrab(popup_child_host_view_);
+    if (CanRendererHandleEvent(event, mouse_locked_, is_selection_popup) &&
+        !(event->flags() & ui::EF_FROM_TOUCH)) {
+      // Confirm existing composition text on mouse press, to make sure
+      // the input caret won't be moved with an ongoing composition text.
+      if (event->type() == ui::ET_MOUSE_PRESSED)
+        FinishImeCompositionSession();
+
+      blink::WebMouseEvent mouse_event = ui::MakeWebMouseEvent(
+          *event, base::Bind(&GetScreenLocationFromEvent));
+      ModifyEventMovementAndCoords(&mouse_event);
+      if (ShouldRouteEvent(event)) {
+        host_->delegate()->GetInputEventRouter()->RouteMouseEvent(host_view_,
+                                                                  &mouse_event);
+      } else {
+        ProcessMouseEvent(mouse_event, *event->latency());
+      }
+
+      // Ensure that we get keyboard focus on mouse down as a plugin window may
+      // have grabbed keyboard focus.
+      if (event->type() == ui::ET_MOUSE_PRESSED)
+        SetKeyboardFocus();
+    }
+  }
+
+  switch (event->type()) {
+    case ui::ET_MOUSE_PRESSED:
+      window_->SetCapture();
+      break;
+    case ui::ET_MOUSE_RELEASED:
+      if (!delegate_->NeedsMouseCapture())
+        window_->ReleaseCapture();
+      break;
+    default:
+      break;
+  }
+
+  if (!IsXButtonUpEvent(event))
+    event->SetHandled();
+}
+
+void RenderWidgetHostViewEventHandler::OnScrollEvent(ui::ScrollEvent* event) {
+  TRACE_EVENT0("input", "RenderWidgetHostViewBase::OnScrollEvent");
+
+  if (event->type() == ui::ET_SCROLL) {
+#if !defined(OS_WIN)
+    // TODO(ananta)
+    // Investigate if this is true for Windows 8 Metro ASH as well.
+    if (event->finger_count() != 2)
+      return;
+#endif
+    blink::WebGestureEvent gesture_event = ui::MakeWebGestureEventFlingCancel();
+    // Coordinates need to be transferred to the fling cancel gesture only
+    // for Surface-targeting to ensure that it is targeted to the correct
+    // RenderWidgetHost.
+    gesture_event.x = event->x();
+    gesture_event.y = event->y();
+    blink::WebMouseWheelEvent mouse_wheel_event = ui::MakeWebMouseWheelEvent(
+        *event, base::Bind(&GetScreenLocationFromEvent));
+    if (ShouldRouteEvent(event)) {
+      host_->delegate()->GetInputEventRouter()->RouteGestureEvent(
+          host_view_, &gesture_event, ui::LatencyInfo());
+      host_->delegate()->GetInputEventRouter()->RouteMouseWheelEvent(
+          host_view_, &mouse_wheel_event);
+    } else {
+      host_->ForwardGestureEvent(gesture_event);
+      host_->ForwardWheelEventWithLatencyInfo(mouse_wheel_event,
+                                              *event->latency());
+    }
+    RecordAction(base::UserMetricsAction("TrackpadScroll"));
+  } else if (event->type() == ui::ET_SCROLL_FLING_START ||
+             event->type() == ui::ET_SCROLL_FLING_CANCEL) {
+    blink::WebGestureEvent gesture_event = ui::MakeWebGestureEvent(
+        *event, base::Bind(&GetScreenLocationFromEvent));
+    if (ShouldRouteEvent(event)) {
+      host_->delegate()->GetInputEventRouter()->RouteGestureEvent(
+          host_view_, &gesture_event, ui::LatencyInfo());
+    } else {
+      host_->ForwardGestureEvent(gesture_event);
+    }
+    if (event->type() == ui::ET_SCROLL_FLING_START)
+      RecordAction(base::UserMetricsAction("TrackpadScrollFling"));
+  }
+
+  event->SetHandled();
+}
+
+void RenderWidgetHostViewEventHandler::OnTouchEvent(ui::TouchEvent* event) {
+  TRACE_EVENT0("input", "RenderWidgetHostViewBase::OnTouchEvent");
+
+  bool had_no_pointer = !pointer_state_.GetPointerCount();
+
+  // Update the touch event first.
+  if (!pointer_state_.OnTouch(*event)) {
+    event->StopPropagation();
+    return;
+  }
+
+  blink::WebTouchEvent touch_event;
+  bool handled =
+      delegate_->selection_controller()->WillHandleTouchEvent(pointer_state_);
+  if (handled) {
+    event->SetHandled();
+  } else {
+    touch_event = ui::CreateWebTouchEventFromMotionEvent(
+        pointer_state_, event->may_cause_scrolling());
+  }
+  pointer_state_.CleanupRemovedTouchPoints(*event);
+
+  if (handled)
+    return;
+
+  if (had_no_pointer)
+    delegate_->selection_controller_client()->OnTouchDown();
+  if (!pointer_state_.GetPointerCount())
+    delegate_->selection_controller_client()->OnTouchUp();
+
+  // It is important to always mark events as being handled asynchronously when
+  // they are forwarded. This ensures that the current event does not get
+  // processed by the gesture recognizer before events currently awaiting
+  // dispatch in the touch queue.
+  event->DisableSynchronousHandling();
+
+  // Set unchanged touch point to StateStationary for touchmove and
+  // touchcancel to make sure only send one ack per WebTouchEvent.
+  MarkUnchangedTouchPointsAsStationary(&touch_event, event->touch_id());
+  if (ShouldRouteEvent(event)) {
+    host_->delegate()->GetInputEventRouter()->RouteTouchEvent(
+        host_view_, &touch_event, *event->latency());
+  } else {
+    ProcessTouchEvent(touch_event, *event->latency());
+  }
+}
+
+void RenderWidgetHostViewEventHandler::OnGestureEvent(ui::GestureEvent* event) {
+  TRACE_EVENT0("input", "RenderWidgetHostViewBase::OnGestureEvent");
+
+  if ((event->type() == ui::ET_GESTURE_PINCH_BEGIN ||
+       event->type() == ui::ET_GESTURE_PINCH_UPDATE ||
+       event->type() == ui::ET_GESTURE_PINCH_END) &&
+      !pinch_zoom_enabled_) {
+    event->SetHandled();
+    return;
+  }
+
+  HandleGestureForTouchSelection(event);
+  if (event->handled())
+    return;
+
+  // Confirm existing composition text on TAP gesture, to make sure the input
+  // caret won't be moved with an ongoing composition text.
+  if (event->type() == ui::ET_GESTURE_TAP)
+    FinishImeCompositionSession();
+
+  blink::WebGestureEvent gesture =
+      ui::MakeWebGestureEvent(*event, base::Bind(&GetScreenLocationFromEvent));
+  if (event->type() == ui::ET_GESTURE_TAP_DOWN) {
+    // Webkit does not stop a fling-scroll on tap-down. So explicitly send an
+    // event to stop any in-progress flings.
+    blink::WebGestureEvent fling_cancel = gesture;
+    fling_cancel.type = blink::WebInputEvent::GestureFlingCancel;
+    fling_cancel.sourceDevice = blink::WebGestureDeviceTouchscreen;
+    if (ShouldRouteEvent(event)) {
+      host_->delegate()->GetInputEventRouter()->RouteGestureEvent(
+          host_view_, &fling_cancel, ui::LatencyInfo());
+    } else {
+      host_->ForwardGestureEvent(fling_cancel);
+    }
+  }
+
+  if (gesture.type != blink::WebInputEvent::Undefined) {
+    if (ShouldRouteEvent(event)) {
+      host_->delegate()->GetInputEventRouter()->RouteGestureEvent(
+          host_view_, &gesture, *event->latency());
+    } else {
+      host_->ForwardGestureEventWithLatencyInfo(gesture, *event->latency());
+    }
+
+    if (event->type() == ui::ET_GESTURE_SCROLL_BEGIN ||
+        event->type() == ui::ET_GESTURE_SCROLL_UPDATE ||
+        event->type() == ui::ET_GESTURE_SCROLL_END) {
+      RecordAction(base::UserMetricsAction("TouchscreenScroll"));
+    } else if (event->type() == ui::ET_SCROLL_FLING_START) {
+      RecordAction(base::UserMetricsAction("TouchscreenScrollFling"));
+    }
+  }
+
+  // If a gesture is not processed by the webpage, then WebKit processes it
+  // (e.g. generates synthetic mouse events).
+  event->SetHandled();
+}
+
+bool RenderWidgetHostViewEventHandler::CanRendererHandleEvent(
+    const ui::MouseEvent* event,
+    bool mouse_locked,
+    bool selection_popup) const {
+  if (event->type() == ui::ET_MOUSE_CAPTURE_CHANGED)
+    return false;
+
+  if (event->type() == ui::ET_MOUSE_EXITED) {
+    if (mouse_locked || selection_popup)
+      return false;
+#if defined(OS_WIN)
+    // Don't forward the mouse leave message which is received when the context
+    // menu is displayed by the page. This confuses the page and causes state
+    // changes.
+    if (host_view_->IsShowingContextMenu())
+      return false;
+#endif
+    return true;
+  }
+
+#if defined(OS_WIN)
+  // Renderer cannot handle WM_XBUTTON or NC events.
+  switch (event->native_event().message) {
+    case WM_XBUTTONDOWN:
+    case WM_XBUTTONUP:
+    case WM_XBUTTONDBLCLK:
+    case WM_NCMOUSELEAVE:
+    case WM_NCMOUSEMOVE:
+    case WM_NCLBUTTONDOWN:
+    case WM_NCLBUTTONUP:
+    case WM_NCLBUTTONDBLCLK:
+    case WM_NCRBUTTONDOWN:
+    case WM_NCRBUTTONUP:
+    case WM_NCRBUTTONDBLCLK:
+    case WM_NCMBUTTONDOWN:
+    case WM_NCMBUTTONUP:
+    case WM_NCMBUTTONDBLCLK:
+    case WM_NCXBUTTONDOWN:
+    case WM_NCXBUTTONUP:
+    case WM_NCXBUTTONDBLCLK:
+      return false;
+    default:
+      break;
+  }
+#elif defined(USE_X11)
+  // Renderer only supports standard mouse buttons, so ignore programmable
+  // buttons.
+  switch (event->type()) {
+    case ui::ET_MOUSE_PRESSED:
+    case ui::ET_MOUSE_RELEASED: {
+      const int kAllowedButtons = ui::EF_LEFT_MOUSE_BUTTON |
+                                  ui::EF_MIDDLE_MOUSE_BUTTON |
+                                  ui::EF_RIGHT_MOUSE_BUTTON;
+      return (event->flags() & kAllowedButtons) != 0;
+    }
+    default:
+      break;
+  }
+#endif
+  return true;
+}
+
+void RenderWidgetHostViewEventHandler::FinishImeCompositionSession() {
+  if (!host_view_->GetTextInputClient()->HasCompositionText())
+    return;
+
+  TextInputManager* text_input_manager = host_view_->GetTextInputManager();
+  if (!!text_input_manager && !!text_input_manager->GetActiveWidget())
+    text_input_manager->GetActiveWidget()->ImeFinishComposingText(false);
+  host_view_->ImeCancelComposition();
+}
+
+void RenderWidgetHostViewEventHandler::ForwardMouseEventToParent(
+    ui::MouseEvent* event) {
+  // Needed to propagate mouse event to |window_->parent()->delegate()|, but
+  // note that it might be something other than a WebContentsViewAura instance.
+  // TODO(pkotwicz): Find a better way of doing this.
+  // In fullscreen mode which is typically used by flash, don't forward
+  // the mouse events to the parent. The renderer and the plugin process
+  // handle these events.
+  if (host_view_->is_fullscreen())
+    return;
+
+  if (event->flags() & ui::EF_FROM_TOUCH)
+    return;
+
+  if (!window_->parent() || !window_->parent()->delegate())
+    return;
+
+  // Take a copy of |event|, to avoid ConvertLocationToTarget mutating the
+  // event.
+  std::unique_ptr<ui::Event> event_copy = ui::Event::Clone(*event);
+  ui::MouseEvent* mouse_event = static_cast<ui::MouseEvent*>(event_copy.get());
+  mouse_event->ConvertLocationToTarget(window_, window_->parent());
+  window_->parent()->delegate()->OnMouseEvent(mouse_event);
+  if (mouse_event->handled())
+    event->SetHandled();
+}
+
+RenderViewHostDelegateView*
+RenderWidgetHostViewEventHandler::GetRenderViewHostDelegateView() {
+  // Use RenderViewHostDelegate to get to the WebContentsViewAura, which will
+  // actually show the disambiguation popup.
+  RenderViewHost* rvh = RenderViewHost::From(host_);
+  if (!rvh)
+    return nullptr;
+
+  RenderViewHostDelegate* delegate = rvh->GetDelegate();
+  if (!delegate)
+    return nullptr;
+
+  return delegate->GetDelegateView();
+}
+
+void RenderWidgetHostViewEventHandler::HandleGestureForTouchSelection(
+    ui::GestureEvent* event) {
+  switch (event->type()) {
+    case ui::ET_GESTURE_LONG_PRESS:
+      if (delegate_->selection_controller()->WillHandleLongPressEvent(
+              event->time_stamp(), event->location_f())) {
+        event->SetHandled();
+      }
+      break;
+    case ui::ET_GESTURE_TAP:
+      if (delegate_->selection_controller()->WillHandleTapEvent(
+              event->location_f(), event->details().tap_count())) {
+        event->SetHandled();
+      }
+      break;
+    case ui::ET_GESTURE_SCROLL_BEGIN:
+      delegate_->selection_controller_client()->OnScrollStarted();
+      break;
+    case ui::ET_GESTURE_SCROLL_END:
+      delegate_->selection_controller_client()->OnScrollCompleted();
+      break;
+#if defined(OS_WIN)
+    case ui::ET_GESTURE_LONG_TAP: {
+      if (!last_context_menu_params_)
+        break;
+
+      std::unique_ptr<ContextMenuParams> context_menu_params =
+          std::move(last_context_menu_params_);
+
+      // On Windows we want to display the context menu when the long press
+      // gesture is released. To achieve that, we switch the saved context
+      // menu params source type to MENU_SOURCE_TOUCH. This is to ensure that
+      // the RenderWidgetHostViewBase::OnShowContextMenu function which is
+      // called from the ShowContextMenu call below, does not treat it as
+      // a context menu request coming in from the long press gesture.
+      DCHECK(context_menu_params->source_type == ui::MENU_SOURCE_LONG_PRESS);
+      context_menu_params->source_type = ui::MENU_SOURCE_TOUCH;
+
+      RenderViewHostDelegateView* delegate_view =
+          GetRenderViewHostDelegateView();
+      if (delegate_view)
+        delegate_view->ShowContextMenu(delegate_->GetFocusedFrame(),
+                                       *context_menu_params);
+
+      event->SetHandled();
+      // WARNING: we may have been deleted during the call to ShowContextMenu().
+      break;
+    }
+#endif
+    default:
+      break;
+  }
+}
+
+void RenderWidgetHostViewEventHandler::HandleMouseEventWhileLocked(
+    ui::MouseEvent* event) {
+  aura::client::CursorClient* cursor_client =
+      aura::client::GetCursorClient(window_->GetRootWindow());
+
+  DCHECK(!cursor_client || !cursor_client->IsCursorVisible());
+
+  if (event->type() == ui::ET_MOUSEWHEEL) {
+    blink::WebMouseWheelEvent mouse_wheel_event =
+        ui::MakeWebMouseWheelEvent(static_cast<ui::MouseWheelEvent&>(*event),
+                                   base::Bind(&GetScreenLocationFromEvent));
+    if (mouse_wheel_event.deltaX != 0 || mouse_wheel_event.deltaY != 0)
+      host_->ForwardWheelEvent(mouse_wheel_event);
+    return;
+  }
+
+  gfx::Point center(gfx::Rect(window_->bounds().size()).CenterPoint());
+
+  // If we receive non client mouse messages while we are in the locked state
+  // it probably means that the mouse left the borders of our window and
+  // needs to be moved back to the center.
+  if (event->flags() & ui::EF_IS_NON_CLIENT) {
+    synthetic_move_sent_ = true;
+    window_->MoveCursorTo(center);
+    return;
+  }
+
+  blink::WebMouseEvent mouse_event =
+      ui::MakeWebMouseEvent(*event, base::Bind(&GetScreenLocationFromEvent));
+
+  bool is_move_to_center_event = (event->type() == ui::ET_MOUSE_MOVED ||
+                                  event->type() == ui::ET_MOUSE_DRAGGED) &&
+                                 mouse_event.x == center.x() &&
+                                 mouse_event.y == center.y();
+
+  // For fractional scale factors, the conversion from pixels to dip and
+  // vice versa could result in off by 1 or 2 errors which hurts us because
+  // we want to avoid sending the artificial move to center event to the
+  // renderer. Sending the move to center to the renderer cause the cursor
+  // to bounce around the center of the screen leading to the lock operation
+  // not working correctly.
+  // Workaround is to treat a mouse move or drag event off by at most 2 px
+  // from the center as a move to center event.
+  if (synthetic_move_sent_ &&
+      IsFractionalScaleFactor(host_view_->current_device_scale_factor())) {
+    if (event->type() == ui::ET_MOUSE_MOVED ||
+        event->type() == ui::ET_MOUSE_DRAGGED) {
+      if ((abs(mouse_event.x - center.x()) <= 2) &&
+          (abs(mouse_event.y - center.y()) <= 2)) {
+        is_move_to_center_event = true;
+      }
+    }
+  }
+
+  ModifyEventMovementAndCoords(&mouse_event);
+
+  bool should_not_forward = is_move_to_center_event && synthetic_move_sent_;
+  if (should_not_forward) {
+    synthetic_move_sent_ = false;
+  } else {
+    // Check if the mouse has reached the border and needs to be centered.
+    if (ShouldMoveToCenter()) {
+      synthetic_move_sent_ = true;
+      window_->MoveCursorTo(center);
+    }
+    bool is_selection_popup = NeedsInputGrab(popup_child_host_view_);
+    // Forward event to renderer.
+    if (CanRendererHandleEvent(event, mouse_locked_, is_selection_popup) &&
+        !(event->flags() & ui::EF_FROM_TOUCH)) {
+      host_->ForwardMouseEvent(mouse_event);
+      // Ensure that we get keyboard focus on mouse down as a plugin window
+      // may have grabbed keyboard focus.
+      if (event->type() == ui::ET_MOUSE_PRESSED)
+        SetKeyboardFocus();
+    }
+  }
+}
+
+void RenderWidgetHostViewEventHandler::ModifyEventMovementAndCoords(
+    blink::WebMouseEvent* event) {
+  // If the mouse has just entered, we must report zero movementX/Y. Hence we
+  // reset any global_mouse_position set previously.
+  if (event->type == blink::WebInputEvent::MouseEnter ||
+      event->type == blink::WebInputEvent::MouseLeave)
+    global_mouse_position_.SetPoint(event->globalX, event->globalY);
+
+  // Movement is computed by taking the difference of the new cursor position
+  // and the previous. Under mouse lock the cursor will be warped back to the
+  // center so that we are not limited by clipping boundaries.
+  // We do not measure movement as the delta from cursor to center because
+  // we may receive more mouse movement events before our warp has taken
+  // effect.
+  event->movementX = event->globalX - global_mouse_position_.x();
+  event->movementY = event->globalY - global_mouse_position_.y();
+
+  global_mouse_position_.SetPoint(event->globalX, event->globalY);
+
+  // Under mouse lock, coordinates of mouse are locked to what they were when
+  // mouse lock was entered.
+  if (mouse_locked_) {
+    event->x = unlocked_mouse_position_.x();
+    event->y = unlocked_mouse_position_.y();
+    event->windowX = unlocked_mouse_position_.x();
+    event->windowY = unlocked_mouse_position_.y();
+    event->globalX = unlocked_global_mouse_position_.x();
+    event->globalY = unlocked_global_mouse_position_.y();
+  } else {
+    unlocked_mouse_position_.SetPoint(event->x, event->y);
+    unlocked_global_mouse_position_.SetPoint(event->globalX, event->globalY);
+  }
+}
+
+void RenderWidgetHostViewEventHandler::SetKeyboardFocus() {
+#if defined(OS_WIN)
+  if (window_ && window_->delegate()->CanFocus()) {
+    aura::WindowTreeHost* host = window_->GetHost();
+    if (host) {
+      gfx::AcceleratedWidget hwnd = host->GetAcceleratedWidget();
+      if (!(::GetWindowLong(hwnd, GWL_EXSTYLE) & WS_EX_NOACTIVATE))
+        ::SetFocus(hwnd);
+    }
+  }
+#endif
+  // TODO(wjmaclean): can host_ ever be null?
+  if (host_ && set_focus_on_mouse_down_or_key_event_) {
+    set_focus_on_mouse_down_or_key_event_ = false;
+    host_->Focus();
+  }
+}
+
+bool RenderWidgetHostViewEventHandler::ShouldMoveToCenter() {
+  gfx::Rect rect = window_->bounds();
+  rect = delegate_->ConvertRectToScreen(rect);
+  int border_x = rect.width() * kMouseLockBorderPercentage / 100;
+  int border_y = rect.height() * kMouseLockBorderPercentage / 100;
+
+  return global_mouse_position_.x() < rect.x() + border_x ||
+         global_mouse_position_.x() > rect.right() - border_x ||
+         global_mouse_position_.y() < rect.y() + border_y ||
+         global_mouse_position_.y() > rect.bottom() - border_y;
+}
+
+bool RenderWidgetHostViewEventHandler::ShouldRouteEvent(
+    const ui::Event* event) const {
+  // We should route an event in two cases:
+  // 1) Mouse events are routed only if cross-process frames are possible.
+  // 2) Touch events are always routed. In the absence of a BrowserPlugin
+  //    we expect the routing to always send the event to this view. If
+  //    one or more BrowserPlugins are present, then the event may be targeted
+  //    to one of them, or this view. This allows GuestViews to have access to
+  //    them while still forcing pinch-zoom to be handled by the top-level
+  //    frame. TODO(wjmaclean): At present, this doesn't work for OOPIF, but
+  //    it should be a simple extension to modify RenderWidgetHostViewChildFrame
+  //    in a similar manner to RenderWidgetHostViewGuest.
+  bool result = host_->delegate() && host_->delegate()->GetInputEventRouter() &&
+                !disable_input_event_router_for_testing_;
+  // ScrollEvents get transformed into MouseWheel events, and so are treated
+  // the same as mouse events for routing purposes.
+  if (event->IsMouseEvent() || event->type() == ui::ET_SCROLL)
+    result = result && SiteIsolationPolicy::AreCrossProcessFramesPossible();
+  return result;
+}
+
+void RenderWidgetHostViewEventHandler::ProcessMouseEvent(
+    const blink::WebMouseEvent& event,
+    const ui::LatencyInfo& latency) {
+  host_->ForwardMouseEventWithLatencyInfo(event, latency);
+}
+
+void RenderWidgetHostViewEventHandler::ProcessMouseWheelEvent(
+    const blink::WebMouseWheelEvent& event,
+    const ui::LatencyInfo& latency) {
+  host_->ForwardWheelEventWithLatencyInfo(event, latency);
+}
+
+void RenderWidgetHostViewEventHandler::ProcessTouchEvent(
+    const blink::WebTouchEvent& event,
+    const ui::LatencyInfo& latency) {
+  host_->ForwardTouchEventWithLatencyInfo(event, latency);
+}
+
+}  // namespace content