WIP: Migrate Wiki content over to src/docs

docs/info_bar_extension_api.md

+# Introduction
+
+Lots of extensions want to show infobars for various reasons. Though the infobars usually follow the pattern of a string of text and a few buttons, they sometimes also want to show richer controls.

[Bons, 2015/08/20 20:16:50]

propose to delete

+
+This proposal is to add an API to chrome to let extensions show infobars backed by HTML.
+
+
+# Details
+
+Since infobars do not take up any persistent space in the UI, they do not need to be registered in the manifest.
+
+Their programmatic API is very simple:
+
+```
+// Shows an infobar in the specified tab. The infobar will be closed automatically when the tab
+// navigates. Use window.close() to close the infobar before then. If no |tabId| is specified
+// the infobar will open in the currently selected tab.
+void chrome.experimental.infobars.show({optional int tabId, string htmlPath}, optional void callback(window));
+
+```
+
+Infobars are scoped to the lifetime of a document, similar to page actions. When the document they are attached to is navigated or closed, they disappear automatically.
+
+# Display
+
+The HTML rendered inside the infobar should get some default CSS that automatically makes the the layout look like a Chrome infobar.
+
+Extension infobars should be limited to a max of 2x the size of current Chrome native infobars.
+
+# Open Questions
+
+  * What happens when multiple infobars (either extension infobars or native ones) are displayed on the same tab?