Create 4 UMAs in histograms.xml:
'FileBrowser.Open.File'
'FileBrowser.Open.GoogleDoc'
'FileBrowser.Open.Subdirectory'
'FileBrowser.Open.UnsupportedFile'

Create 1 new enum in enums.xml:
FileBrowser.OpenType:
- OPEN_BUTTON_MAIN_MENU
- OPEN_BUTTON_RIGHT_CLICK_MENU
- DOUBLE_CLICK
- ENTER

Then use metrics.recordEnum() to record the action for each of these cases.

For an idea of how to implement, see the existing DirectoryTree expansion UMA in-progress at: https://chromium-review.googlesource.com/c/chromium/src/+/954774

The available metrics methods are in metrics_base.js: https://cs.chromium.org/chromium/src/ui/file_manager/file_manager/common/js/metrics_base.js?type=cs&sq=package:chromium
 

Create 4 UMAs in histograms.xml:
'FileBrowser.Open.File'
'FileBrowser.Open.GoogleDoc'
'FileBrowser.Open.Subdirectory'
'FileBrowser.Open.UnsupportedFile'

Create 1 new enum in enums.xml:
FileBrowser.OpenType:
- OPEN_BUTTON_MAIN_MENU
- OPEN_BUTTON_RIGHT_CLICK_MENU
- DOUBLE_CLICK
- ENTER

FileBrowser.App.OpenWith
- SINGLE_APP
- DEFAULT_APP
- NON_DEFAULT_APP
- NO_APP

Then use metrics.recordEnum() to record the action for each of these cases.

For an idea of how to implement, see the existing DirectoryTree expansion UMA in-progress at: https://chromium-review.googlesource.com/c/chromium/src/+/954774

The available metrics methods are in metrics_base.js: https://cs.chromium.org/chromium/src/ui/file_manager/file_manager/common/js/metrics_base.js?type=cs&sq=package:chromium