Fix an issue while opening app indexing developer tool.

In the personal app indexing testing tool, for the
"open developer tool" button:

1. Initialize ADB when the button is shown.

2. Hide the error message if the user cancelled while selecting
device.

3. Run the ADB command in a separate thread pool.

Test: N/A
Change-Id: Ie32ad38456e7c680b06cba08999d173bc61f2803
(cherry picked from commit 2c58d76df3fcc7842dda1b5b03badb899eb871bc)
8 files changed
tree: 1e5973c6da104f9d7f337d148ec486ea255b494d
  1. lib/
  2. resources/
  3. src/
  4. testData/
  5. testSrc/
  6. BUILD
  7. google-appindexing.iml