data:text/html,chromewebdata

The "data:text/html,chromewebdata" URL value (called kUnreachableWebDataURL in Chromium) is loaded whenever a URL fails to load in a frame (for example, via RenderFrameImpl::didFailProvisionalLoad and LoadNavigationErrorPage). The issue you explained is kind of a bug where Android WebView built on chromium fails to loads the page in question due unmapped ssl error. Chromium is an open-source Web browser project started by Google, to provide the source code for the proprietary Google Chrome browser . The core of older versions of Android Open Source Project (AOSP) browser is still Chromium. Android Kit kat WebView component built on chromium is unable to open web page due to an unmapped ssl error! It is usually occurring on secure login pages presented by captive portals.

Android Open Source Project (AOSP)

Android is developed by Google until the latest changes and updates are ready to be released, at which point the source code is made available to the Android Open Source Project (AOSP). The Android Open Source Project (AOSP) is an initiative created to guide development of the Android mobile platform. The Android platform consists of the operating system (OS), middleware and integral mobile applications.

Chromium

Chromium is an open-source project licensed under a BSD license. It includes third-party software licensed under terms ranging from public domain to one-off licenses. Google Chrome is a custom build of Chromium distributed by Google. Chrome includes additional software components licensed by Google that are not granted to the Chromium project.