Add Mojo API for Blink hit testing

content/common/input/input_handler.mojom

 // Copyright 2017 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.
 
 module content.mojom;
 
 import "mojo/common/string16.mojom";
 import "services/ui/public/interfaces/ime/ime.mojom";
 import "ui/gfx/geometry/mojo/geometry.mojom";
 
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   Redo();
   Cut();
   Copy();
   CopyToFindPboard();
   Paste();
   PasteAndMatchStyle();
   Delete();
   SelectAll();
   CollapseSelection();
 
+  // Returns the hit-tested remote frame id for the given coordinates.

[rjkroege, 2017/06/26 18:29:52]

how are we suppose to use this API from ui/ws? Couldn't this be a component?

[Navid Zolghadr, 2017/07/17 18:54:45]

riajiang@ I believe you have written some code that expect to use this code
based on what Robert said before. Can you point me to that code so I can work on
exposing this API to that part of the code?

+  HitTestFrameAt(gfx.mojom.PointF point) => (int32 frame_id);

[rjkroege, 2017/06/26 18:29:52]

What is your expectation of the coordinate system of point? I've been presuming
that the CTS of point is the CTS of the target frame?

API seems reasonable to me.

[riajiang, 2017/06/27 16:37:28]

Input |point| would be in display-coordinate-pixels (or I can convert it to
screen-coordinates before asking blink) and we need to update it to be in
target's CTS after we found the target |frame_id|?

[rjkroege, 2017/06/28 18:40:19]

display coordinate pixels is  likely wrong. I claim x,y w.r.t. the target frame

[Navid Zolghadr, 2017/06/28 19:25:06]

Essentially you are asking frame X to tell you the target frame of a point. That
point should be translated to the coordinate space of Frame X. Meaning that if
Frame X was rotated in its parent then it has no idea that it happened and you
need to transform the event accordingly for that frame X understands it.

+
   // Replaces the selected region or a word around the cursor with the
   // specified string.
   Replace(mojo.common.mojom.String16 word);
 
   // Replaces the misspelling in the selected region with the specified string.
   ReplaceMisspelling(mojo.common.mojom.String16 word);
 
   // Requests the renderer to select the region between two points.
   // Expects a SelectRange_ACK message when finished.
   SelectRange(gfx.mojom.Point base, gfx.mojom.Point extent);
 
   // Sent by the browser to ask the renderer to adjust the selection start and
   // end points by the given amounts. A negative amount moves the selection
   // towards the beginning of the document, a positive amount moves the
   // selection towards the end of the document.
   AdjustSelectionByCharacterOffset(int32 start, int32 end);
 
   // Requests the renderer to move the selection extent point to a new position.
   // Expects a MoveRangeSelectionExtent_ACK message when finished.
   MoveRangeSelectionExtent(gfx.mojom.Point extent);
 
   // TODO(dtapuska): Implement WidgetInputHandler.
   // GetWidgetInputHandler(associated WidgetInputHandler& interface_request);
 };