Suppress context menu on virtual keyboard to fix crash

ui/keyboard/content/keyboard_ui_content.cc

 // Copyright (c) 2013 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 "ui/keyboard/content/keyboard_ui_content.h"
 
 #include "base/command_line.h"
 #include "base/macros.h"
 #include "base/values.h"
 #include "content/public/browser/render_widget_host.h"
@@ skipping 77 matching lines @@
   }
 
   // Overridden from content::WebContentsDelegate:
   void RequestMediaAccessPermission(
       content::WebContents* web_contents,
       const content::MediaStreamRequest& request,
       const content::MediaResponseCallback& callback) override {
     ui_->RequestAudioInput(web_contents, request, callback);
   }
 
+  // Overridden from content::WebContentsDelegate:
+  bool PreHandleGestureEvent(content::WebContents* source,
+                             const blink::WebGestureEvent& event) override {
+    switch (event.type()) {
+      // Scroll events are not suppressed because the menu to select IME should
+      // be scrollable.
+      case blink::WebInputEvent::GestureScrollBegin:
+      case blink::WebInputEvent::GestureScrollEnd:
+      case blink::WebInputEvent::GestureScrollUpdate:
+      case blink::WebInputEvent::GestureFlingStart:
+      case blink::WebInputEvent::GestureFlingCancel:
+        return false;
+      default:
+        // Stop gesture events from being passed to renderer to suppress the
+        // context menu. crbug.com/685140
+        return true;
+    }
+  }
+
   // Overridden from content::WebContentsObserver:
   void WebContentsDestroyed() override { delete this; }
 
   keyboard::KeyboardUIContent* ui_;
 
   DISALLOW_COPY_AND_ASSIGN(KeyboardContentsDelegate);
 };
 
 }  // namespace
 
@@ skipping 220 matching lines @@
           keyboard_controller()->keyboard_visible());
 }
 
 void KeyboardUIContent::AddBoundsChangedObserver(aura::Window* window) {
   aura::Window* target_window = window ? window->GetToplevelWindow() : nullptr;
   if (target_window)
     window_bounds_observer_->AddObservedWindow(target_window);
 }
 
 }  // namespace keyboard