add getting result image by find by image

[KazuCocoa]

closes appium/appium#12506

What this will do

• Store the result of find by image in ImageElement
  • It is available only when getMatchedImageResult is true via settings API
• Users can get the data via getAttribute API as visual
  • e.g. Ruby: element.visual, Python: element.getAttribute('visual') etc

The visual

example in Ruby

> @driver.update_settings({ fixImageTemplateScale: true, getMatchedImageResult: false })=> nil
> @core.wait { @@driver.find_element_by_image AppiumLibCoreTest.path_of('test/functional/data/test_ios_button.png') }
=> #<Selenium::WebDriver::Element:0x7144c4bf699ffe78 id="appium-image-element-758743a6-7c14-4a90-932c-be7d247faef8">
> image_element.visual
=> nil
> @driver.update_settings({ fixImageTemplateScale: true, getMatchedImageResult: true })=> nil
> image_element = @@core.wait { @@driver.find_element_by_image AppiumLibCoreTest.path_of('test/functional/data/test_ios_button.png') }
=> #<Selenium::WebDriver::Element:0x..f814fd569a6a19222 id="appium-image-element-efb92580-e72a-4d96-9a61-4ea45137cd27">
> v = image_element.visual
=> "iVBORw0KGgoAAAANSUhEUgAAAXcAAAKbCAIAAACBzF3NAAAgAElEQVR4AezBC5SP1f4A/O/e+7n9rnM1YxgOE5FQ+QspoRDFTG6FiKKYRhqGSaHkLk0qJKEc5VqoSTdJF+pBShlyN+aMGcx9frfnuvd+1/tb76zVWvWuznSylnM8nw969NFHweFwOK4YtG/fPnA4HI4rBu3fvx8cDofjikH79u0Dh8PhuGKQqqrwR2zbBgBCiCAIUAchZNs2/FW6rjPGAMDv99u2DX+VbdsIIYyxIAiGYSCEOOeMMYwxIQRjzDnXdd3tdiOEDMMQBAGuJZRSqCPLMgBwziml8BuEEF3XEUKKoti2DX9EFMVIJMIYkySJUooQwhgjhACAc84Y41HwG7IsM8Y0TXO5XPAbnHPGGOccIQR1LMuSZRkhZBiGLMvwG5xzAMAYc87BUX+UUhSFMdY0Df4qWZYjkUhMTE..."
> image_element.unsupported_attribute
Selenium::WebDriver::Error::UnknownMethodError: Method has not yet been implemented
from NotYetImplementedError: Method has not yet been implemented

---

Will add this debug feature in http://appium.io/docs/en/advanced-concepts/image-elements/

[jlipps]

great idea!

[jlipps]

pretty sure this else block is not necessary (without a break or return, the default case will also be executed)

[KazuCocoa]

Yes, but the lint claimed about this point.
I compared adding an ignoring the lint message vs adding this else block.

Which is safer in JS world? (I thought following the lint was safer for now.)

[atimofeev86]

what about c#?