Moving input device hotplug event processing outside of ui/display

ash/touch/touchscreen_util.cc

Index: ash/touch/touchscreen_util.cc
diff --git a/ash/touch/touchscreen_util.cc b/ash/touch/touchscreen_util.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b7f0b994ae7d2678ca93093858522ece54acbe1d
--- /dev/null
+++ b/ash/touch/touchscreen_util.cc
@@ -0,0 +1,103 @@
+// 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.
+
+#include "ash/touch/touchscreen_util.h"
+
+#include <set>
+
+#include "base/logging.h"
+
+namespace ash {
+
+void AssociateTouchscreens(std::vector<DisplayInfo>* displays,
+                           const std::vector<ui::TouchscreenDevice>& devices) {
+  std::set<int> no_match_touchscreen;
+  int internal_touchscreen = -1;
+  for (size_t i = 0; i < devices.size(); ++i) {
+    if (devices[i].is_internal) {
+      internal_touchscreen = i;
+      break;
+    }
+  }
+
+  DisplayInfo* internal_state = NULL;
+  for (size_t i = 0; i < displays->size(); ++i) {
+    DisplayInfo* state = &(*displays)[i];
+    if (state->id() == gfx::Display::InternalDisplayId() &&
+        !state->GetNativeModeSize().IsEmpty() &&
+        state->touch_support() == gfx::Display::TOUCH_SUPPORT_UNKNOWN) {
+      internal_state = state;
+      break;
+    }
+  }
+
+  if (internal_state && internal_touchscreen >= 0) {
+    internal_state->set_touch_device_id(devices[internal_touchscreen].id);
+    internal_state->set_touch_support(gfx::Display::TOUCH_SUPPORT_AVAILABLE);
+    VLOG(2) << "Found internal touchscreen for internal display "
+            << internal_state->id() << " touch_device_id "
+            << internal_state->touch_device_id() << " size "
+            << devices[internal_touchscreen].size.ToString();
+  }
+
+  for (size_t i = 0; i < devices.size(); ++i) {
+    if (internal_state && internal_state->touch_device_id() == devices[i].id)
+      continue;
+
+    bool found_mapping = false;
+    for (size_t j = 0; j < displays->size(); ++j) {
+      DisplayInfo* state = &(*displays)[j];
+      const gfx::Size native_size = state->GetNativeModeSize();
+      if (state->touch_support() == gfx::Display::TOUCH_SUPPORT_AVAILABLE ||
+          native_size.IsEmpty())
+        continue;
+
+      // Allow 1 pixel difference between screen and touchscreen
+      // resolutions. Because in some cases for monitor resolution
+      // 1024x768 touchscreen's resolution would be 1024x768, but for
+      // some 1023x767. It really depends on touchscreen's firmware
+      // configuration.
+      if (std::abs(native_size.width() - devices[i].size.width()) <= 1 &&
+          std::abs(native_size.height() - devices[i].size.height()) <= 1) {
+        state->set_touch_device_id(devices[i].id);
+        state->set_touch_support(gfx::Display::TOUCH_SUPPORT_AVAILABLE);
+
+        VLOG(2) << "Found touchscreen for display " << state->id()
+                << " touch_device_id " << state->touch_device_id() << " size "
+                << devices[i].size.ToString();
+        found_mapping = true;
+        break;
+      }
+    }
+
+    if (!found_mapping) {
+      no_match_touchscreen.insert(devices[i].id);
+      VLOG(2) << "No matching display for touch_device_id " << devices[i].id
+              << " size " << devices[i].size.ToString();
+    }
+  }
+
+  // Sometimes we can't find a matching screen for the touchscreen, e.g.
+  // due to the touchscreen's reporting range having no correlation with the
+  // screen's resolution. In this case, we arbitrarily assign unmatched
+  // touchscreens to unmatched screens.
+  for (std::set<int>::iterator it = no_match_touchscreen.begin();
+       it != no_match_touchscreen.end();
+       ++it) {
+    for (size_t i = 0; i < displays->size(); ++i) {
+      DisplayInfo* state = &(*displays)[i];
+      if (state->id() != gfx::Display::InternalDisplayId() &&
+          !state->GetNativeModeSize().IsEmpty() &&
+          state->touch_support() == gfx::Display::TOUCH_SUPPORT_UNKNOWN) {
+        state->set_touch_device_id(*it);
+        state->set_touch_support(gfx::Display::TOUCH_SUPPORT_AVAILABLE);
+        VLOG(2) << "Arbitrarily matching touchscreen "
+                << state->touch_device_id() << " to display " << state->id();
+        break;
+      }
+    }
+  }
+}
+
+}  // namespace ash