diff --git a/third_party/WebKit/LayoutTests/http/tests/security/media-element-audio-source-node-redirect-expected.txt b/third_party/WebKit/LayoutTests/http/tests/security/media-element-audio-source-node-redirect-expected.txt
new file mode 100644
index 0000000..c1ba686
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/http/tests/security/media-element-audio-source-node-redirect-expected.txt
@@ -0,0 +1,11 @@
+CONSOLE WARNING: line 21: The Web Audio autoplay policy will be re-enabled in Chrome 70 (October 2018). Please check that your website is compatible with it. https://goo.gl/7K7WLu
+CONSOLE MESSAGE: MediaElementAudioSource outputs zeroes due to CORS access restrictions for http://127.0.0.1:8000/serviceworker/resources/redirect.php?Redirect=http://localhost:8000/security/resources/webaudio/laughter.wav
+MediaElementAudioSourceNode with redirection
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+PASS All samples correctly zeroed.
+PASS successfullyParsed is true
+
+TEST COMPLETE
+
diff --git a/third_party/WebKit/LayoutTests/http/tests/security/media-element-audio-source-node-redirect.html b/third_party/WebKit/LayoutTests/http/tests/security/media-element-audio-source-node-redirect.html
new file mode 100644
index 0000000..a166ec87
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/http/tests/security/media-element-audio-source-node-redirect.html
@@ -0,0 +1,41 @@
+<!doctype html>
+<html>
+  <head>
+    <script src="resources/webaudio/compatibility.js"></script>
+    <script src="resources/webaudio/media-element-audio-source-node-test.js"></script>
+    <script src="/js-test-resources/js-test.js"></script>
+  </head>
+
+  <body>
+    <div id="description"></div>
+    <div id="console"></div>
+
+    <script>
+      description("MediaElementAudioSourceNode with redirection");
+
+      var src = "/serviceworker/resources/redirect.php?Redirect=http://localhost:8000/security/resources/webaudio/laughter.wav";
+      var data;
+
+      function checkResult (e) {
+        data = e.getChannelData(0);
+        var count = 0;
+
+        // Count the number of non-zero values. Since this is a cross-origin source, all the values
+        // should be zero.
+        for (var k = 0; k < data.length; ++k) {
+            if (data[k] != 0) {
+                ++count;
+            }
+        }
+        if (count > 0) {
+            testFailed("Expected all zeros but found " + count + " non-zero values out of " + data.length + ".");
+        } else {
+            testPassed("All samples correctly zeroed.");
+        }
+      }
+
+      runTest(src, checkResult);
+
+    </script>
+  </body>
+</html>
diff --git a/third_party/WebKit/LayoutTests/http/tests/security/resources/webaudio/media-element-audio-source-node-test.js b/third_party/WebKit/LayoutTests/http/tests/security/resources/webaudio/media-element-audio-source-node-test.js
index 20a5463..58c6699 100644
--- a/third_party/WebKit/LayoutTests/http/tests/security/resources/webaudio/media-element-audio-source-node-test.js
+++ b/third_party/WebKit/LayoutTests/http/tests/security/resources/webaudio/media-element-audio-source-node-test.js
@@ -41,6 +41,8 @@
         context.resume().then(() => {
                               spn.onaudioprocess = function(e) {
                                 checkResult(e.inputBuffer);
+                                // Stop the context so we don't keep getting called anymore.
+                                context.close();
                                 finishJSTest();
                               }
           });
diff --git a/third_party/blink/renderer/modules/webaudio/base_audio_context.cc b/third_party/blink/renderer/modules/webaudio/base_audio_context.cc
index 1bde585..44244ea 100644
--- a/third_party/blink/renderer/modules/webaudio/base_audio_context.cc
+++ b/third_party/blink/renderer/modules/webaudio/base_audio_context.cc
@@ -1058,4 +1058,21 @@
   }
 }
 
+bool BaseAudioContext::WouldTaintOrigin(const KURL& url) const {
+  // Data URLs don't taint the origin.
+  if (url.ProtocolIsData()) {
+    return false;
+  }
+
+  Document* document = GetDocument();
+  if (document && document->GetSecurityOrigin()) {
+    // The origin is tainted if and only if we cannot read content from the URL.
+    return !document->GetSecurityOrigin()->CanRequest(url);
+  }
+
+  // Be conservative and assume it's tainted if it's not a data url and if we
+  // can't get the security origin of the document.
+  return true;
+}
+
 }  // namespace blink
diff --git a/third_party/blink/renderer/modules/webaudio/base_audio_context.h b/third_party/blink/renderer/modules/webaudio/base_audio_context.h
index 0132fd6d..c24b333 100644
--- a/third_party/blink/renderer/modules/webaudio/base_audio_context.h
+++ b/third_party/blink/renderer/modules/webaudio/base_audio_context.h
@@ -346,6 +346,13 @@
   // Does nothing when the worklet global scope does not exist.
   void UpdateWorkletGlobalScopeOnRenderingThread();
 
+  // Returns true if the URL would taint the origin so that we shouldn't be
+  // allowing media to played through webaudio.
+  // TODO(crbug.com/845913): This should really be on an AudioContext.  Move
+  // this when we move the media stuff from BaseAudioContext to AudioContext, as
+  // requried by the spec.
+  bool WouldTaintOrigin(const KURL& url) const;
+
  protected:
   enum ContextType { kRealtimeContext, kOfflineContext };
 
diff --git a/third_party/blink/renderer/modules/webaudio/media_element_audio_source_node.cc b/third_party/blink/renderer/modules/webaudio/media_element_audio_source_node.cc
index 128b81d..d55da1f 100644
--- a/third_party/blink/renderer/modules/webaudio/media_element_audio_source_node.cc
+++ b/third_party/blink/renderer/modules/webaudio/media_element_audio_source_node.cc
@@ -48,10 +48,7 @@
       media_element_(media_element),
       source_number_of_channels_(0),
       source_sample_rate_(0),
-      passes_current_src_cors_access_check_(
-          PassesCurrentSrcCORSAccessCheck(media_element.currentSrc())),
-      maybe_print_cors_message_(!passes_current_src_cors_access_check_),
-      current_src_string_(media_element.currentSrc().GetString()) {
+      is_origin_tainted_(false) {
   DCHECK(IsMainThread());
   // Default to stereo. This could change depending on what the media element
   // .src is set to.
@@ -87,6 +84,12 @@
 
 void MediaElementAudioSourceHandler::SetFormat(size_t number_of_channels,
                                                float source_sample_rate) {
+  bool is_tainted = WouldTaintOrigin();
+
+  if (is_tainted) {
+    PrintCORSMessage(MediaElement()->currentSrc().GetString());
+  }
+
   if (number_of_channels != source_number_of_channels_ ||
       source_sample_rate != source_sample_rate_) {
     if (!number_of_channels ||
@@ -99,13 +102,16 @@
       Locker<MediaElementAudioSourceHandler> locker(*this);
       source_number_of_channels_ = 0;
       source_sample_rate_ = 0;
+      is_origin_tainted_ = is_tainted;
       return;
     }
 
-    // Synchronize with process() to protect m_sourceNumberOfChannels,
-    // m_sourceSampleRate, and m_multiChannelResampler.
+    // Synchronize with process() to protect |source_number_of_channels_|,
+    // |source_sample_rate_|, |multi_channel_resampler_|. and
+    // |is_origin_tainted_|.
     Locker<MediaElementAudioSourceHandler> locker(*this);
 
+    is_origin_tainted_ = is_tainted;
     source_number_of_channels_ = number_of_channels;
     source_sample_rate_ = source_sample_rate;
 
@@ -128,36 +134,20 @@
   }
 }
 
-bool MediaElementAudioSourceHandler::PassesCORSAccessCheck() {
-  DCHECK(MediaElement());
+bool MediaElementAudioSourceHandler::WouldTaintOrigin() {
+  // If we're cross-origin and allowed access vie CORS, we're not tainted.
+  if (MediaElement()->GetWebMediaPlayer()->DidPassCORSAccessCheck()) {
+    return false;
+  }
 
-  return (MediaElement()->GetWebMediaPlayer() &&
-          MediaElement()->GetWebMediaPlayer()->DidPassCORSAccessCheck()) ||
-         passes_current_src_cors_access_check_;
-}
+  // Handles the case where the url is a redirect to another site that we're not
+  // allowed to access.
+  if (!MediaElement()->HasSingleSecurityOrigin()) {
+    return true;
+  }
 
-void MediaElementAudioSourceHandler::OnCurrentSrcChanged(
-    const KURL& current_src) {
-  DCHECK(IsMainThread());
-
-  // Synchronize with process().
-  Locker<MediaElementAudioSourceHandler> locker(*this);
-
-  passes_current_src_cors_access_check_ =
-      PassesCurrentSrcCORSAccessCheck(current_src);
-
-  // Make a note if we need to print a console message and save the |curentSrc|
-  // for use in the message.  Need to wait until later to print the message in
-  // case HTMLMediaElement allows access.
-  maybe_print_cors_message_ = !passes_current_src_cors_access_check_;
-  current_src_string_ = current_src.GetString();
-}
-
-bool MediaElementAudioSourceHandler::PassesCurrentSrcCORSAccessCheck(
-    const KURL& current_src) {
-  DCHECK(IsMainThread());
-  return Context()->GetSecurityOrigin() &&
-         Context()->GetSecurityOrigin()->CanRequest(current_src);
+  // Test to see if the current media URL taint the origin of the audio context?
+  return Context()->WouldTaintOrigin(MediaElement()->currentSrc());
 }
 
 void MediaElementAudioSourceHandler::PrintCORSMessage(const String& message) {
@@ -206,16 +196,7 @@
       provider.ProvideInput(output_bus, number_of_frames);
     }
     // Output silence if we don't have access to the element.
-    if (!PassesCORSAccessCheck()) {
-      if (maybe_print_cors_message_) {
-        // Print a CORS message, but just once for each change in the current
-        // media element source, and only if we have a document to print to.
-        maybe_print_cors_message_ = false;
-        PostCrossThreadTask(
-            *task_runner_, FROM_HERE,
-            CrossThreadBind(&MediaElementAudioSourceHandler::PrintCORSMessage,
-                            WrapRefCounted(this), current_src_string_));
-      }
+    if (is_origin_tainted_) {
       output_bus->Zero();
     }
   } else {
@@ -300,10 +281,6 @@
                                                 sample_rate);
 }
 
-void MediaElementAudioSourceNode::OnCurrentSrcChanged(const KURL& current_src) {
-  GetMediaElementAudioSourceHandler().OnCurrentSrcChanged(current_src);
-}
-
 void MediaElementAudioSourceNode::lock() {
   GetMediaElementAudioSourceHandler().lock();
 }
diff --git a/third_party/blink/renderer/modules/webaudio/media_element_audio_source_node.h b/third_party/blink/renderer/modules/webaudio/media_element_audio_source_node.h
index fdc16a8..311d563c 100644
--- a/third_party/blink/renderer/modules/webaudio/media_element_audio_source_node.h
+++ b/third_party/blink/renderer/modules/webaudio/media_element_audio_source_node.h
@@ -61,7 +61,6 @@
   // Helpers for AudioSourceProviderClient implementation of
   // MediaElementAudioSourceNode.
   void SetFormat(size_t number_of_channels, float sample_rate);
-  void OnCurrentSrcChanged(const KURL& current_src);
   void lock() EXCLUSIVE_LOCK_FUNCTION(GetProcessLock());
   void unlock() UNLOCK_FUNCTION(GetProcessLock());
 
@@ -78,11 +77,9 @@
   // As an audio source, we will never propagate silence.
   bool PropagatesSilence() const override { return false; }
 
-  // Must be called only on the audio thread.
-  bool PassesCORSAccessCheck();
-
-  // Must be called only on the main thread.
-  bool PassesCurrentSrcCORSAccessCheck(const KURL& current_src);
+  // Returns true if the origin of the media element is tainted so that the
+  // audio should be muted when playing through WebAudio.
+  bool WouldTaintOrigin();
 
   // Print warning if CORS restrictions cause MediaElementAudioSource to output
   // zeroes.
@@ -102,23 +99,13 @@
 
   std::unique_ptr<MultiChannelResampler> multi_channel_resampler_;
 
-  // |m_passesCurrentSrcCORSAccessCheck| holds the value of
-  // context()->getSecurityOrigin() &&
-  // context()->getSecurityOrigin()->canRequest(mediaElement()->currentSrc()),
-  // updated in the ctor and onCurrentSrcChanged() on the main thread and used
-  // in passesCORSAccessCheck() on the audio thread, protected by
-  // |m_processLock|.
-  bool passes_current_src_cors_access_check_;
-
-  // Indicates if we need to print a CORS message if the current source has
-  // changed and we have no access to it. Must be protected by |m_processLock|.
-  bool maybe_print_cors_message_;
-
-  // The value of mediaElement()->currentSrc().string() in the ctor and
-  // onCurrentSrcChanged().  Protected by |m_processLock|.
-  String current_src_string_;
-
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+
+  // True if the orgin would be tainted by the media element.  In this case,
+  // this node outputs silence.  This can happen if the media element source is
+  // a cross-origin source which we're not allowed to access due to CORS
+  // restrictions.
+  bool is_origin_tainted_;
 };
 
 class MediaElementAudioSourceNode final : public AudioNode,
@@ -142,7 +129,6 @@
 
   // AudioSourceProviderClient functions:
   void SetFormat(size_t number_of_channels, float sample_rate) override;
-  void OnCurrentSrcChanged(const KURL& current_src) override;
   void lock() override EXCLUSIVE_LOCK_FUNCTION(
       GetMediaElementAudioSourceHandler().GetProcessLock());
   void unlock() override