amp-ima-video: Markdown README for project (#9336)

* Added README for amp-ima-video.

Fixed IMA SDK link.

Really fixed IMA SDK link.

Fixed again.

Added space

Fixed overvie wheader.

Removed slash file.

* Fixed closing tag.

* Updated to resolve comments.

* Updated to address missed comments

* Updated to resolve comments.

* Fix comma -> period.

extensions/amp-ima-video/0.1/validator-amp-ima-video.protoascii

@@ -53,10 +53,7 @@ tags: {  # <amp-ima-video>
   attr_lists: "extended-amp-global"
   spec_url: "https://www.ampproject.org/docs/reference/components/amp-ima-video"
   amp_layout: {
-    supported_layouts: FILL
     supported_layouts: FIXED
-    supported_layouts: FIXED_HEIGHT
-    supported_layouts: NODISPLAY
     supported_layouts: RESPONSIVE
   }
 }

extensions/amp-ima-video/amp-ima-video.md

@@ -0,0 +1,90 @@
+<!---
+Copyright 2017 The AMP HTML Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS-IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+
+# <a name="amp-ima-video"></a> `amp-ima-video`
+
+<table>
+  <tr>
+    <td width="40%"><strong>Description</strong></td>
+    <td>Embeds a video player for instream video ads that are integrated with
+    the
+    <a href="https://developers.google.com/interactive-media-ads/docs/sdks/html5/">IMA SDK</a>.
+    </td>
+  </tr>
+  <tr>
+    <td width="40%"><strong>Availability</strong></td>
+    <td>Experimental</td>
+  </tr>
+  <tr>
+    <td width="40%"><strong>Required Script</strong></td>
+    <td><code>&lt;script async custom-element="amp-ima-video" src="https://cdn.ampproject.org/v0/amp-ima-video-0.1.js">&lt;/script></code></td>
+  </tr>
+  <tr>
+    <td class="col-fourty"><strong><a href="https://www.ampproject.org/docs/guides/responsive/control_layout.html">Supported Layouts</a></strong></td>
+    <td>fixed, responsive</td>
+  </tr>
+  <tr>
+    <td width="40%"><strong>Examples</strong></td>
+    <td>None</td>
+  </tr>
+</table>
+
+## Overview
+
+You can use the `amp-ima-video` component to embed an <a
+href="https://developers.google.com/interactive-media-ads/docs/sdks/html5/">IMA
+SDK</a> enabled video player.
+
+To embed a video, provide a source URL for your
+content video (`data-src`) and an ad tag (`data-tag`), which is a URL to a
+VAST-compliant ad response (for examples, see
+[IMA Sample Tags](https://developers.google.com/interactive-media-ads/docs/sdks/html5/tags)).
+
+**Example: Embedding a video**
+
+```html
+<amp-ima-video
+    width=640 height=360 layout="responsive"
+    data-src="https://s0.2mdn.net/4253510/google_ddm_animation_480P.mp4"
+    data-tag="https://pubads.g.doubleclick.net/gampad/ads?sz=640x480&iu=/124319096/external/ad_rule_samples&ciu_szs=300x250&ad_rule=1&impl=s&gdfp_req=1&env=vp&output=vmap&unviewed_position_start=1&cust_params=deployment%3Ddevsite%26sample_ar%3Dpremidpost&cmsid=496&vid=short_onecue&correlator="
+    data-poster="path/to/poster.png">
+</amp-ima-video>
+```
+
+## Attributes
+
+**data-src** (required)
+
+The URL of your video content.
+
+**data-tag** (required)
+
+The URL for your VAST ad document.
+
+**data-poster** (optional)
+
+An image for the frame to be displayed before video playback has started. By
+default, the first frame is displayed.
+
+**common attributes**
+
+This element includes
+[common attributes](https://www.ampproject.org/docs/reference/common_attributes)
+extended to AMP components.
+
+## Validation
+
+See [amp-ima-video rules](https://github.com/ampproject/amphtml/blob/master/extensions/amp-ima-video/0.1/validator-amp-ima-video.protoascii) in the AMP validator specification.