Adds readme files for every mv3 sample (GoogleChrome#973)

* Adds readme files for every mv3 sample

* Update api-samples/alarms/README.md

Co-authored-by: Joe Medley <[email protected]>

* Update api-samples/alarms/README.md

Co-authored-by: Joe Medley <[email protected]>

* Update api-samples/override/blank_ntp/README.md

Co-authored-by: Joe Medley <[email protected]>

* Update api-samples/omnibox/new-tab-search/README.md

Co-authored-by: Joe Medley <[email protected]>

* Update api-samples/omnibox/new-tab-search/README.md

Co-authored-by: Joe Medley <[email protected]>

* Update api-samples/contextMenus/global_context_search/README.md

Co-authored-by: Joe Medley <[email protected]>

* Update api-samples/cookies/cookie-clearer/README.md

Co-authored-by: Joe Medley <[email protected]>

* Update api-samples/default_command_override/README.md

Co-authored-by: Joe Medley <[email protected]>

* Update api-samples/il8n/README.md

Co-authored-by: Joe Medley <[email protected]>

* Update api-samples/il8n/README.md

Co-authored-by: Joe Medley <[email protected]>

* Update api-samples/default_command_override/README.md

Co-authored-by: Joe Medley <[email protected]>

* Update api-samples/favicon/README.md

Co-authored-by: Joe Medley <[email protected]>

* Update api-samples/favicon/README.md

Co-authored-by: Joe Medley <[email protected]>

* Update api-samples/override/blank_ntp/README.md

Co-authored-by: Joe Medley <[email protected]>

* Update api-samples/fontSettings/fontSettings Basic/README.md

Co-authored-by: Joe Medley <[email protected]>

* Update README.md

* Update api-samples/fontSettings/fontSettings Basic/README.md

Co-authored-by: Joe Medley <[email protected]>

* Updates omnibox sample with small clarity improvement

---------

Co-authored-by: Joe Medley <[email protected]>

api-samples/alarms/README.md

@@ -0,0 +1,14 @@
+# chrome.browsingData
+
+This sample demonstrates the `chrome.alarms` API by allowing the user to set alarms using an extension page.
+
+## Overview
+
+The extension calls `chrome.alarms.create()` to set an initial alarm that is displayed on the extension page. More alarms can be set with user input.
+
+## Running this extension
+
+1. Clone this repository.
+2. Load this directory in Chrome as an [unpacked extension](https://developer.chrome.com/docs/extensions/mv3/getstarted/development-basics/#load-unpacked).
+3. Pin the extension to the taskbar to access the action button.
+4. Open the extension popup by clicking the action button and interact with the UI.

api-samples/contextMenus/global_context_search/README.md

@@ -0,0 +1,15 @@
+# chrome.contextMenus
+
+This sample demonstrates the `chrome.contextMenus` API by letting a user switch between searching different countries' versions of Google via a `contextMenu`.
+
+## Overview
+
+The extension uses `chrome.contextMenus.create()` to populate the context menu with locale options based on an options menu in the popup. A `chrome.contextMenus.onClicked.addListener()` event will open a specific locale's Google homepage when one of the extension's context menu options are clicked.
+
+## Running this extension
+
+1. Clone this repository.
+2. Load this directory in Chrome as an [unpacked extension](https://developer.chrome.com/docs/extensions/mv3/getstarted/development-basics/#load-unpacked).
+3. Pin the extension to the taskbar to access the action button.
+4. Open the extension popup by clicking the action button and interact with the UI.
+5. Right click within the browser to view and interact with the context menu.

api-samples/cookies/cookie-clearer/README.md

@@ -0,0 +1,14 @@
+# chrome.cookies
+
+This sample demonstrates the `chrome.cookies` API by letting a user delete their cookies via a popup UI.
+
+## Overview
+
+The extension uses `chrome.cookies.getAll()` and `chrome.cookies.remove()` to delete the user's cookies when prompted.
+
+## Running this extension
+
+1. Clone this repository.
+2. Load this directory in Chrome as an [unpacked extension](https://developer.chrome.com/docs/extensions/mv3/getstarted/development-basics/#load-unpacked).
+3. Pin the extension to the taskbar to access the action button.
+4. Open the extension popup by clicking the action button and interact with the UI.

api-samples/default_command_override/README.md

@@ -0,0 +1,13 @@
+# chrome.cookies
+
+This sample demonstrates the `chrome.commands` API by creating a new keyboard macro for switching tabs in the browser window.
+
+## Overview
+
+The extension sets Ctrl+Shift+Left and Ctrl+Shift+Right as command inputs in the manifest, and uses `chrome.commands.onCommand.addListener()` to trigger switching tabs.
+
+## Running this extension
+
+1. Clone this repository.
+2. Load this directory in Chrome as an [unpacked extension](https://developer.chrome.com/docs/extensions/mv3/getstarted/development-basics/#load-unpacked).
+3. Input the keyboard commands to switch between tabs.

api-samples/favicon/README.md

@@ -0,0 +1,14 @@
+# favicon
+
+This sample demonstrates the favicon manifest permission by displaying the favicon of a url in the extension popup.
+
+## Overview
+
+The extension calls `chrome.runtime.getURL('/_favicon/')` to create a fully-qualified URL pointing to the "\_favicon/" folder. Then it returns a new string representing the URL with several query parameters. Finally, the extension appends the image to the body of the extension popup.
+
+## Running this extension
+
+1. Clone this repository.
+2. Load this directory in Chrome as an [unpacked extension](https://developer.chrome.com/docs/extensions/mv3/getstarted/development-basics/#load-unpacked).
+3. Pin the extension to the taskbar to access the action button.
+4. Open the extension popup by clicking the action button.

api-samples/fontSettings/fontSettings Basic/README.md

@@ -0,0 +1,14 @@
+# chrome.fontSettings
+
+This extension demonstrates the `chrome.fontSettings` API by allowing users to modify the size of fonts on webpages.
+
+## Overview
+
+The extension creates a user interface in the extension's options page that allows users to see and modify font settings using `chrome.fontSettings` to change parameters.
+
+## Running this extension
+
+1. Clone this repository.
+2. Load this directory in Chrome as an [unpacked extension](https://developer.chrome.com/docs/extensions/mv3/getstarted/development-basics/#load-unpacked).
+3. Pin th extension to the taskbar and click the action button.
+4. Click the extension's action button to visit the popup page.

api-samples/il8n/README.md

@@ -0,0 +1,14 @@
+# chrome.i18n
+
+This sample demonstrates the `chrome.i18n` API by localizing text in the extension popup.
+
+## Overview
+
+The extension includes localized translations of its UI text in the `\_locales\' folder. It then calls `chrome.i18n.getMessage()` to populate the text in the extension UI with either French or English, depending on the current language setting.
+
+## Running this extension
+
+1. Clone this repository.
+2. Load this directory in Chrome as an [unpacked extension](https://developer.chrome.com/docs/extensions/mv3/getstarted/development-basics/#load-unpacked).
+3. Pin the extension to the taskbar to access the action button.
+4. Open the extension popup by clicking the action button.

api-samples/omnibox/new-tab-search/README.md

@@ -0,0 +1,13 @@
+# chrome.omnibox
+
+This sample demonstrates the `"omnibox"` manifest key and API by creating a keyword that opens up a browser search in a new tab.
+
+## Overview
+
+The extension uses the `"omnibox"` manifest key and its parameter `"keyword"`. When `chrome.omnibox.onInputEntered.addListener()` is called and the keyword 'newTab' is used, a new tab is opened with a google search for the user's input text.
+
+## Running this extension
+
+1. Clone this repository.
+2. Load this directory in Chrome as an [unpacked extension](https://developer.chrome.com/docs/extensions/mv3/getstarted/development-basics/#load-unpacked).
+3. Type 'newTab' and some text you wish to google within the browser omnibox.

api-samples/omnibox/new-tab-search/manifest.json

@@ -1,12 +1,12 @@
 {
   "name": "Omnibox - New Tab Search",
-  "description": "Type 'nt' plus a search term into the Omnibox to open search in new tab.",
+  "description": "Type 'newTab' plus a search term into the Omnibox to open search in new tab.",
   "version": "1.0",
   "manifest_version": 3,
   "background": {
     "service_worker": "background.js"
   },
-  "omnibox": { "keyword": "nt" },
+  "omnibox": { "keyword": "newTab" },
   "action": {
     "default_icon": {
       "16": "newtab_search16.png",

api-samples/override/blank_ntp/README.md

@@ -0,0 +1,13 @@
+# "chrome_url_overrides"
+
+This sample demonstrates the ` "chrome_url_overrides"` manifest key by replacing the user's default New Tab page with a new html file.
+
+## Overview
+
+The extension calls ` "chrome_url_overrides"` and its parameter `"newtab"` to replace the New Tab page with blank.html.
+
+## Running this extension
+
+1. Clone this repository.
+2. Load this directory in Chrome as an [unpacked extension](https://developer.chrome.com/docs/extensions/mv3/getstarted/development-basics/#load-unpacked).
+3. Open a new tab while the extension is enabled.