html_viewer: Correctly set axis and orientation of MotionEvent.

MotionEvent's orientation is in radian, and it falls within [-π/2, π/2). However,
TouchEvent's rotation-angle is in degrees, and it falls within [0, 180). So make
sure the conversion from rotation-angle to orientation happens correctly. Add
PointerProperties::SetAxisAndOrientation() as a convenience function to do this
correctly.

This fixes a crash in mandoline when touching the screen in landspace mode.

BUG=none

Review URL: https://codereview.chromium.org/1202283005

Cr-Commit-Position: refs/heads/master@{#336187}

4 files changed, 92 insertions, 34 deletions

diff --git a/ui/events/gesture_detection/motion_event_generic.cc b/ui/events/gesture_detection/motion_event_generic.cc
index 2f2c34b..a90c72a 100644
--- a/ui/events/gesture_detection/motion_event_generic.cc
+++ b/ui/events/gesture_detection/motion_event_generic.cc
@@ -2,8 +2,13 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// MSVC++ requires this to be set before any other includes to get M_PI.
+#define _USE_MATH_DEFINES
+
 #include "ui/events/gesture_detection/motion_event_generic.h"
 
+#include <cmath>
+
 #include "base/logging.h"
 #include "ui/events/base_event_utils.h"
 
@@ -42,6 +47,37 @@ PointerProperties::PointerProperties(const MotionEvent& event,
       source_device_id(0) {
 }
 
+void PointerProperties::SetAxesAndOrientation(float radius_x,
+                                              float radius_y,
+                                              float rotation_angle_degree) {
+  DCHECK(!touch_major && !touch_minor && !orientation);
+  float rotation_angle_rad = rotation_angle_degree * M_PI / 180.f;
+  DCHECK_GE(radius_x, 0) << "Unexpected x-radius < 0 (" << radius_x << ")";
+  DCHECK_GE(radius_y, 0) << "Unexpected y-radius < 0 (" << radius_y << ")";
+  DCHECK(0 <= rotation_angle_rad && rotation_angle_rad < M_PI)
+      << "Unexpected touch rotation angle " << rotation_angle_rad << " rad";
+
+  // Make the angle acute to ease subsequent logic. The angle range effectively
+  // changes from [0, pi) to [0, pi/2).
+  if (rotation_angle_rad >= M_PI_2) {
+    rotation_angle_rad -= static_cast<float>(M_PI_2);
+    std::swap(radius_x, radius_y);
+  }
+
+  if (radius_x > radius_y) {
+    // The case radius_x == radius_y is omitted from here on purpose: for
+    // circles, we want to pass the angle (which could be any value in such
+    // cases but always seem to be set to zero) unchanged.
+    touch_major = 2.f * radius_x;
+    touch_minor = 2.f * radius_y;
+    orientation = rotation_angle_rad - M_PI_2;
+  } else {
+    touch_major = 2.f * radius_y;
+    touch_minor = 2.f * radius_x;
+    orientation = rotation_angle_rad;
+  }
+}
+
 MotionEventGeneric::MotionEventGeneric(Action action,
                                        base::TimeTicks event_time,
                                        const PointerProperties& pointer)
diff --git a/ui/events/gesture_detection/motion_event_generic.h b/ui/events/gesture_detection/motion_event_generic.h
index 6357342..2a9a606 100644
--- a/ui/events/gesture_detection/motion_event_generic.h
+++ b/ui/events/gesture_detection/motion_event_generic.h
@@ -18,6 +18,12 @@ struct GESTURE_DETECTION_EXPORT PointerProperties {
   PointerProperties(float x, float y, float touch_major);
   PointerProperties(const MotionEvent& event, size_t pointer_index);
 
+  // Sets |touch_major|, |touch_minor|, and |orientation| from the given radius
+  // and rotation angle (in degrees).
+  void SetAxesAndOrientation(float radius_x,
+                             float radius_y,
+                             float rotation_angle_degree);
+
   int id;
   MotionEvent::ToolType tool_type;
   float x;
diff --git a/ui/events/gesture_detection/motion_event_generic_unittest.cc b/ui/events/gesture_detection/motion_event_generic_unittest.cc
index 182eb1e..2e0294f 100644
--- a/ui/events/gesture_detection/motion_event_generic_unittest.cc
+++ b/ui/events/gesture_detection/motion_event_generic_unittest.cc
@@ -2,6 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// MSVC++ requires this to be set before any other includes to get M_PI.
+#define _USE_MATH_DEFINES
+
+#include <cmath>
+
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/events/event_constants.h"
 #include "ui/events/gesture_detection/motion_event_generic.h"
@@ -177,6 +182,49 @@ TEST(MotionEventGenericTest, RemovePointerAt) {
   EXPECT_EQ(-1, event.FindPointerIndexOfId(0));
 }
 
+TEST(MotionEventGenericTest, AxisAndOrientation) {
+  {
+    PointerProperties properties;
+    float radius_x = 10;
+    float radius_y = 5;
+    float rotation_angle_deg = 0;
+    properties.SetAxesAndOrientation(radius_x, radius_y, rotation_angle_deg);
+    EXPECT_EQ(20, properties.touch_major);
+    EXPECT_EQ(10, properties.touch_minor);
+    EXPECT_NEAR(-M_PI_2, properties.orientation, 0.001);
+  }
+  {
+    PointerProperties properties;
+    float radius_x = 5;
+    float radius_y = 10;
+    float rotation_angle_deg = 0;
+    properties.SetAxesAndOrientation(radius_x, radius_y, rotation_angle_deg);
+    EXPECT_EQ(20, properties.touch_major);
+    EXPECT_EQ(10, properties.touch_minor);
+    EXPECT_NEAR(0, properties.orientation, 0.001);
+  }
+  {
+    PointerProperties properties;
+    float radius_x = 10;
+    float radius_y = 5;
+    float rotation_angle_deg = 179.99f;
+    properties.SetAxesAndOrientation(radius_x, radius_y, rotation_angle_deg);
+    EXPECT_EQ(20, properties.touch_major);
+    EXPECT_EQ(10, properties.touch_minor);
+    EXPECT_NEAR(M_PI_2, properties.orientation, 0.001);
+  }
+  {
+    PointerProperties properties;
+    float radius_x = 10;
+    float radius_y = 5;
+    float rotation_angle_deg = 90;
+    properties.SetAxesAndOrientation(radius_x, radius_y, rotation_angle_deg);
+    EXPECT_EQ(20, properties.touch_major);
+    EXPECT_EQ(10, properties.touch_minor);
+    EXPECT_NEAR(0, properties.orientation, 0.001);
+  }
+}
+
 TEST(MotionEventGenericTest, ToString) {
   base::TimeTicks event_time = base::TimeTicks::Now();
   base::TimeTicks historical_event_time0 =
diff --git a/ui/events/gestures/motion_event_aura.cc b/ui/events/gestures/motion_event_aura.cc
index 01df3f6..8c345f8 100644
--- a/ui/events/gestures/motion_event_aura.cc
+++ b/ui/events/gestures/motion_event_aura.cc
@@ -2,13 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// MSVC++ requires this to be set before any other includes to get M_PI.
-#define _USE_MATH_DEFINES
-
 #include "ui/events/gestures/motion_event_aura.h"
 
-#include <cmath>
-
 #include "base/logging.h"
 #include "ui/events/gesture_detection/gesture_configuration.h"
 
@@ -25,35 +20,8 @@ PointerProperties GetPointerPropertiesFromTouchEvent(const TouchEvent& touch) {
   pointer_properties.pressure = touch.force();
   pointer_properties.source_device_id = touch.source_device_id();
 
-  float radius_x = touch.radius_x();
-  float radius_y = touch.radius_y();
-  float rotation_angle_rad = touch.rotation_angle() * M_PI / 180.f;
-
-  DCHECK_GE(radius_x, 0) << "Unexpected x-radius < 0";
-  DCHECK_GE(radius_y, 0) << "Unexpected y-radius < 0";
-  DCHECK(0 <= rotation_angle_rad && rotation_angle_rad < M_PI)
-      << "Unexpected touch rotation angle";
-
-  // Make the angle acute to ease subsequent logic. The angle range effectively
-  // changes from [0, pi) to [0, pi/2).
-  if (rotation_angle_rad >= M_PI_2) {
-    rotation_angle_rad -= static_cast<float>(M_PI_2);
-    std::swap(radius_x, radius_y);
-  }
-
-  if (radius_x > radius_y) {
-    // The case radius_x == radius_y is omitted from here on purpose: for
-    // circles, we want to pass the angle (which could be any value in such
-    // cases but always seem to be set to zero) unchanged.
-    pointer_properties.touch_major = 2.f * radius_x;
-    pointer_properties.touch_minor = 2.f * radius_y;
-    pointer_properties.orientation = rotation_angle_rad - M_PI_2;
-  } else {
-    pointer_properties.touch_major = 2.f * radius_y;
-    pointer_properties.touch_minor = 2.f * radius_x;
-    pointer_properties.orientation = rotation_angle_rad;
-  }
-
+  pointer_properties.SetAxesAndOrientation(touch.radius_x(), touch.radius_y(),
+                                           touch.rotation_angle());
   if (!pointer_properties.touch_major) {
     pointer_properties.touch_major =
         2.f * GestureConfiguration::GetInstance()->default_radius();