Support chrome-extension:// scheme in URLPattern.

chrome/common/extensions/docs/static/match_patterns.html

Index: chrome/common/extensions/docs/static/match_patterns.html
diff --git a/chrome/common/extensions/docs/static/match_patterns.html b/chrome/common/extensions/docs/static/match_patterns.html
index 871fcfafa05035ffe455545e92f160ff696064e0..36676ab6d2e3710515c9466925c3de37aa137d9f 100644
--- a/chrome/common/extensions/docs/static/match_patterns.html
+++ b/chrome/common/extensions/docs/static/match_patterns.html
@@ -15,7 +15,8 @@ which URLs your content script affects.
 <p>
 A match pattern is essentially a URL
 that begins with a permitted scheme (<code>http</code>,
-<code>https</code>, <code>file</code>, or <code>ftp</code>),
+<code>https</code>, <code>file</code>, <code>ftp</code>, or
+<code>chrome-extension</code>),
 and that can contain '<code>*</code>' characters.
 The special pattern
 <code>&lt;all_urls&gt;</code> matches any URL
@@ -51,7 +52,7 @@ Each match pattern has 3 parts:</p>
 
 <pre>
 <em>&lt;url-pattern&gt;</em> := <em>&lt;scheme&gt;</em>://<em>&lt;host&gt;</em><em>&lt;path&gt;</em>
-<em>&lt;scheme&gt;</em> := '*' | 'http' | 'https' | 'file' | 'ftp'
+<em>&lt;scheme&gt;</em> := '*' | 'http' | 'https' | 'file' | 'ftp' | 'chrome-extension'
 <em>&lt;host&gt;</em> := '*' | '*.' <em>&lt;any char except '/' and '*'&gt;</em>+
 <em>&lt;path&gt;</em> := '/' <em>&lt;any chars&gt;</em>
 </pre>