MacViews: Implement Force Touch/Mac dictionary lookup for Textfields.

ui/views/view.h

 // Copyright (c) 2012 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.
 
 #ifndef UI_VIEWS_VIEW_H_
 #define UI_VIEWS_VIEW_H_
 
 #include <stddef.h>
 
 #include <algorithm>
@@ skipping 31 matching lines @@
 #if defined(OS_WIN)
 #include "base/win/scoped_comptr.h"
 #endif
 
 using ui::OSExchangeData;
 
 namespace gfx {
 class Canvas;
 class Insets;
 class Path;
+class RenderText;
 class Transform;
 }
 
 namespace ui {
 struct AXViewState;
 class Compositor;
 class InputMethod;
 class Layer;
 class NativeTheme;
 class PaintContext;
@@ skipping 504 matching lines @@
   // Returns the View that should be the target of an event having |rect| as
   // its location, or NULL if no such target exists. |rect| is in the local
   // coordinate space of |this|.
   View* GetEventHandlerForRect(const gfx::Rect& rect);
 
   // Returns the deepest visible descendant that contains the specified point
   // and supports tooltips. If the view does not contain the point, returns
   // NULL.
   virtual View* GetTooltipHandlerForPoint(const gfx::Point& point);
 
+  // Returns the RenderText instance corresponding to the view. Currently, only
+  // views which have at most one RenderText instance, should implement this.
+  virtual const gfx::RenderText* GetRenderText() const;

[sky, 2016/09/26 16:20:18]

Can you outline why this needs to be exposed on View? I would prefer consumers
that need to know the type of View they have and operate on it.

[karandeepb, 2016/09/27 01:09:11]

So the problem we want to solve is given a views::View, get the word being
displayed at some given point. This is only needed for Textfields and Labels
currently. Possible approaches-
1) Expose GetRenderText on View.
2) Expose GetWordAtPoint on View. (Subsequently we might also need something
like GetWordForRange).
3) Expose GetTextInputClient on View and add GetWordAtPoint to the
TextInputClient interface. (But Labels don't implement the TextInputClient
interface).
4) Use RTTI at the call site (BridgedContentView) with the help of
View::GetClassName() and static_cast.

I have also outlined these options on the linked doc -
https://docs.google.com/document/d/17QYrMpIXpk-FpGanjhJ-Yx33njNQy7B5oL_bxb7-v...

+  gfx::RenderText* GetRenderText();
+
   // Return the cursor that should be used for this view or the default cursor.
   // The event location is in the receiver's coordinate system. The caller is
   // responsible for managing the lifetime of the returned object, though that
   // lifetime may vary from platform to platform. On Windows and Aura,
   // the cursor is a shared resource.
   virtual gfx::NativeCursor GetCursor(const ui::MouseEvent& event);
 
   // A convenience function which calls HitTestRect() with a rect of size
   // 1x1 and an origin of |point|. |point| is in the local coordinate space
   // of |this|.
@@ skipping 978 matching lines @@
   // Belongs to this view, but it's reference-counted on some platforms
   // so we can't use a scoped_ptr. It's dereferenced in the destructor.
   NativeViewAccessibility* native_view_accessibility_;
 
   DISALLOW_COPY_AND_ASSIGN(View);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_VIEW_H_