Make sure that workspace on android side is within chrome's work area.

Bug: 901538
Test: manually tested with squid.
Change-Id: I06cf91e0bbcc5281f2f4caf65dc84b0f1833087c
Reviewed-on: https://chromium-review.googlesource.com/c/1328161Reviewed-by: Dominik Laskowski <domlaskowski@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606756}

components/exo/wayland/server.cc

@@ -204,6 +204,50 @@ double GetDefaultDeviceScaleFactor() {
   return WMHelper::GetInstance()->GetDefaultDeviceScaleFactor();
 }
 
+// Scale the |child_bounds| in such a way that if it should fill the
+// |parent_size|'s width/height, it returns the |parent_size_in_pixel|'s
+// width/height.
+gfx::Rect ScaleBoundsToPixelSnappedToParent(
+    const gfx::Size& parent_size_in_pixel,
+    const gfx::Size& parent_size,
+    float device_scale_factor,
+    const gfx::Rect& child_bounds) {
+  int right = child_bounds.right();
+  int bottom = child_bounds.bottom();
+
+  int new_x = std::round(child_bounds.x() * device_scale_factor);
+  int new_y = std::round(child_bounds.y() * device_scale_factor);
+
+  int new_right = right == parent_size.width()
+                      ? parent_size_in_pixel.width()
+                      : std::round(right * device_scale_factor);
+
+  int new_bottom = bottom == parent_size.height()
+                       ? parent_size_in_pixel.height()
+                       : std::round(bottom * device_scale_factor);
+
+  return gfx::Rect(new_x, new_y, new_right - new_x, new_bottom - new_y);
+}
+
+// Create the insets make sure that work area will be within the chrome's
+// work area when converted to the pixel on client side.
+// TODO(oshima): We should send these information in pixel so that
+// client do not have to convert it back.
+gfx::Insets GetAdjustedInsets(const display::Display& display) {
+  float scale = display.device_scale_factor();
+  gfx::Size size_in_pixel = display.GetSizeInPixel();
+  gfx::Rect work_area_in_display = display.work_area();
+  work_area_in_display.Offset(-display.bounds().x(), -display.bounds().y());
+  gfx::Rect work_area_in_pixel = ScaleBoundsToPixelSnappedToParent(
+      size_in_pixel, display.bounds().size(), scale, work_area_in_display);
+  gfx::Insets insets_in_pixel =
+      gfx::Rect(size_in_pixel).InsetsFrom(work_area_in_pixel);
+  return gfx::Insets(std::ceil(insets_in_pixel.top() / scale),
+                     std::ceil(insets_in_pixel.left() / scale),
+                     std::ceil(insets_in_pixel.bottom() / scale),
+                     std::ceil(insets_in_pixel.right() / scale));
+}
+
 // Convert a timestamp to a time value that can be used when interfacing
 // with wayland. Note that we cast a int64_t value to uint32_t which can
 // potentially overflow.
@@ -2683,7 +2727,7 @@ class WaylandRemoteShell : public ash::TabletModeObserver,
 
     for (const auto& display : screen->GetAllDisplays()) {
       const gfx::Rect& bounds = display.bounds();
-      const gfx::Insets& insets = display.GetWorkAreaInsets();
+      const gfx::Insets& insets = GetAdjustedInsets(display);
 
       double device_scale_factor = display.device_scale_factor();