Parse meta tag that disables ChromeVox content script and forces compat mode.

chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js

Index: chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js
diff --git a/chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js b/chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js
index 5c5b4dfcd0a3c978021d6a122f9aa5eaa68e0f03..25d317029959eaa1d056771882ef3ec689c347e8 100644
--- a/chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js
+++ b/chrome/browser/resources/chromeos/chromevox/cvox2/background/background.js
@@ -51,6 +51,14 @@ Background = function() {
   this.whitelist_ = ['chromevox_next_test'];
 
   /**
+   * A list of site substring patterns to blacklist ChromeVox Classic,
+   * putting ChromeVox into Compat mode.
+   * @type {!Set<string>}
+   * @private
+   */
+  this.classicBlacklist_ = new Set();
+
+  /**
    * Regular expression for blacklisting classic.
    * @type {RegExp}
    * @private
@@ -230,7 +238,8 @@ Background.prototype = {
     // async. Save it to ensure we're looking at the currentRange at this moment
     // in time.
     var cur = this.currentRange_;
-    chrome.tabs.query({active: true}, function(tabs) {
+    chrome.tabs.query({active: true,
+                       lastFocusedWindow: true}, function(tabs) {
       if (mode === ChromeVoxMode.CLASSIC) {
         // Generally, we don't want to inject classic content scripts as it is
         // done by the extension system at document load. The exception is when
@@ -243,7 +252,7 @@ Background.prototype = {
         if (cur && !cur.isWebRange())
           return;
 
-        this.disableClassicChromeVox_();
+        this.disableClassicChromeVox_(tabs);

[David Tseng, 2016/06/16 21:36:33]

If setting force next mode, we do want to disable all running instances of
classic (including those not in a tab).

[dmazzoni, 2016/06/17 22:20:38]

Good catch. Take a look.

       }
     }.bind(this));
 
@@ -1002,7 +1011,10 @@ Background.prototype = {
    * @private
    */
   isBlacklistedForClassic_: function(url) {
-    return this.classicBlacklistRegExp_.test(url);
+    if (this.classicBlacklistRegExp_.test(url))
+      return true;
+    url = url.substring(0, url.indexOf('#')) || url;
+    return this.classicBlacklist_.has(url);
   },
 
   /**
@@ -1018,12 +1030,16 @@ Background.prototype = {
 
   /**
    * Disables classic ChromeVox in current web content.
+   * @param {Array<Tab>} tabs The tabs where ChromeVox scripts should
+   *     be disabled.
    */
-  disableClassicChromeVox_: function() {
-    cvox.ExtensionBridge.send({
+  disableClassicChromeVox_: function(tabs) {
+    for (var i = 0, tab; tab = tabs[i]; i++) {
+      chrome.tabs.sendMessage(tab.id, {
         message: 'SYSTEM_COMMAND',
         command: 'killChromeVox'
-    });
+      });
+    }
   },
 
   /**
@@ -1075,6 +1091,11 @@ Background.prototype = {
             target: 'next',
             isClassicEnabled: isClassicEnabled
           });
+        } else if (action == 'enableCompatForUrl') {
+          var url = msg['url'];
+          this.classicBlacklist_.add(url);
+          if (this.currentRange_ && this.currentRange_.start.node)
+            this.refreshMode(this.currentRange_.start.node);
         } else if (action == 'onCommand') {
           this.onGotCommand(msg['command']);
         } else if (action == 'flushNextUtterance') {