Implements computation of touch calibration transform using user provided data

ash/touch/touch_transformer_controller.h

 // Copyright 2014 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 ASH_TOUCH_TOUCH_TRANSFORMER_CONTROLLER_H_
 #define ASH_TOUCH_TOUCH_TRANSFORMER_CONTROLLER_H_
 
 #include <stdint.h>
 
 #include "ash/ash_export.h"
@@ skipping 17 matching lines @@
   ~TouchTransformerController() override;
 
   // Updates the TouchTransformer for touch device and pushes the new
   // TouchTransformer into device manager.
   void UpdateTouchTransformer() const;
 
   // WindowTreeHostManager::Observer:
   void OnDisplaysInitialized() override;
   void OnDisplayConfigurationChanged() override;
 
+  // During touch calibration we remove any kind of transform that is being
+  // applied to the touch input's location.

[kylechar, 2016/12/19 20:00:21]

This also updates the transforms right?

[malaykeshav, 2016/12/20 09:56:04]

No. This only sets the TouchTransformerController in a state that returns an
empty transform.
This is required during calibration. We want raw touch inputs that are not
transformed in their local screen space. 

[kylechar, 2016/12/20 17:41:28]

What does the call to UpdateTouchTransformer() do then? It seems like it would
set empty transforms if is_calibrating and properly sets transforms if
!is_calibrating.

[malaykeshav, 2016/12/20 19:16:55]

Correct. When the calibration is under process (See
https://drive.google.com/a/google.com/file/d/0B_WkX8bSkoT1QVR0WFJYdUY2SmZTdWd...
) we want no transform to be applied to the touch inputs since we are trying to
collect data that computes the new calibrated transform.

+  void SetForCalibration(bool is_calibrating);
+
  private:
   FRIEND_TEST_ALL_PREFIXES(TouchTransformerControllerTest,

[kylechar, 2016/12/19 20:00:21]

Would it just be simpler to make TouchTransformerControllerTest a friend class
at this point?

[malaykeshav, 2016/12/20 09:56:05]

Done

[kylechar, 2016/12/20 17:41:28]

This wasn't done?

[malaykeshav, 2016/12/20 19:16:55]

I was unable to friend class TouchTransformerControllerTest for some reason. The
compiler throws private function access error. I will try again when I have
access to corp network tmrw morning. 
Resolving rest of the comments atm.

[malaykeshav, 2016/12/21 05:49:42]

Done

                            MirrorModeLetterboxing);
   FRIEND_TEST_ALL_PREFIXES(TouchTransformerControllerTest,
                            MirrorModePillarboxing);
   FRIEND_TEST_ALL_PREFIXES(TouchTransformerControllerTest, SoftwareMirrorMode);
   FRIEND_TEST_ALL_PREFIXES(TouchTransformerControllerTest, ExtendedMode);
   FRIEND_TEST_ALL_PREFIXES(TouchTransformerControllerTest, TouchRadiusScale);
+  FRIEND_TEST_ALL_PREFIXES(TouchTransformerControllerTest, OzoneTrasnlation);
+  FRIEND_TEST_ALL_PREFIXES(TouchTransformerControllerTest,
+                           AccurateUserTouchCalibration);
+  FRIEND_TEST_ALL_PREFIXES(TouchTransformerControllerTest,
+                           ErrorProneUserTouchCalibration);
+  FRIEND_TEST_ALL_PREFIXES(TouchTransformerControllerTest,
+                           ResolutionChangeUserTouchCalibration);
+  FRIEND_TEST_ALL_PREFIXES(TouchTransformerControllerTest,
+                           DifferentBoundsUserTouchCalibration);
+  FRIEND_TEST_ALL_PREFIXES(TouchTransformerControllerTest,
+                           LetterboxingUserTouchCalibration);
+  FRIEND_TEST_ALL_PREFIXES(TouchTransformerControllerTest,
+                           PillarBoxingUserTouchCalibration);
 
   // Returns a transform that will be used to change an event's location from
   // the touchscreen's coordinate system into |display|'s coordinate system.
   // The transform is also responsible for properly scaling the display if the
   // display supports panel fitting.
   //
   // On X11 events are reported in framebuffer coordinate space, so the
   // |framebuffer_size| is used for scaling.
   // On Ozone events are reported in the touchscreen's resolution, so
   // |touch_display| is used to determine the size and scale the event.
@@ skipping 19 matching lines @@
   // touch events.
   // |touch_display| is the physical display that has the touchscreen
   // from which the events arrive.
   // |target_display| provides the dimensions to which the touch event will be
   // transformed.
   void UpdateTouchTransform(
       int64_t target_display_id,
       const display::ManagedDisplayInfo& touch_display,
       const display::ManagedDisplayInfo& target_display) const;
 
+  bool is_calibrating_ = false;
+
   DISALLOW_COPY_AND_ASSIGN(TouchTransformerController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_TOUCH_TOUCH_TRANSFORMER_CONTROLLER_H_