Throw exceptions for invalid number of channels for ConvolverNode

The ConvolverNode only supports 1, 2 or 4 channels and must throw an
exception for any other number of channels.

BUG=563379
TEST=convolver-channels.html

Review URL: https://codereview.chromium.org/1497803002

Cr-Commit-Position: refs/heads/master@{#363024}

third_party/WebKit/LayoutTests/webaudio/convolver-channels-expected.txt

+Test Supported Number of Channels for ConvolverNode
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+PASS ConvolverNode with buffer of 1 channels did not throw an exception.
+PASS ConvolverNode with buffer of 2 channels did not throw an exception.
+PASS ConvolverNode with buffer of 3 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 3.
+PASS ConvolverNode with buffer of 4 channels did not throw an exception.
+PASS ConvolverNode with buffer of 5 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 5.
+PASS ConvolverNode with buffer of 6 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 6.
+PASS ConvolverNode with buffer of 7 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 7.
+PASS ConvolverNode with buffer of 8 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 8.
+PASS ConvolverNode with buffer of 9 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 9.
+PASS ConvolverNode with buffer of 10 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 10.
+PASS ConvolverNode with buffer of 11 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 11.
+PASS ConvolverNode with buffer of 12 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 12.
+PASS ConvolverNode with buffer of 13 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 13.
+PASS ConvolverNode with buffer of 14 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 14.
+PASS ConvolverNode with buffer of 15 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 15.
+PASS ConvolverNode with buffer of 16 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 16.
+PASS ConvolverNode with buffer of 17 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 17.
+PASS ConvolverNode with buffer of 18 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 18.
+PASS ConvolverNode with buffer of 19 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 19.
+PASS ConvolverNode with buffer of 20 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 20.
+PASS ConvolverNode with buffer of 21 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 21.
+PASS ConvolverNode with buffer of 22 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 22.
+PASS ConvolverNode with buffer of 23 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 23.
+PASS ConvolverNode with buffer of 24 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 24.
+PASS ConvolverNode with buffer of 25 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 25.
+PASS ConvolverNode with buffer of 26 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 26.
+PASS ConvolverNode with buffer of 27 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 27.
+PASS ConvolverNode with buffer of 28 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 28.
+PASS ConvolverNode with buffer of 29 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 29.
+PASS ConvolverNode with buffer of 30 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 30.
+PASS ConvolverNode with buffer of 31 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 31.
+PASS ConvolverNode with buffer of 32 channels threw NotSupportedError: Failed to set the 'buffer' property on 'ConvolverNode': The buffer must have 1, 2, or 4 channels, not 32.
+PASS Multiple channels for the convolver correctly handled.
+PASS successfullyParsed is true
+
+TEST COMPLETE
+

third_party/WebKit/LayoutTests/webaudio/convolver-channels.html

+<!doctype html>
+<html>
+  <head>
+    <script src="../resources/js-test.js"></script>
+    <script src="resources/compatibility.js"></script>
+    <script src="resources/audio-testing.js"></script>
+    <title>Test Supported Number of Channels for ConvolverNode</title>
+  </head>
+
+  <body>
+    <script>
+      description("Test Supported Number of Channels for ConvolverNode");
+      window.jsTestIsAsync = true;
+
+      var audit = Audit.createTaskRunner();
+
+      audit.defineTask("channel-count-test", function (done) {
+        // Just need a context to create nodes on, so any allowed length and rate is ok.
+        var context = new OfflineAudioContext(1, 1, 48000);
+
+        var success = true;
+
+        for (var count = 1; count <= 32; ++count) {
+          var convolver = context.createConvolver();
+          var buffer = context.createBuffer(count, 1, context.sampleRate);
+          var message = "ConvolverNode with buffer of " + count + " channels";
+
+          if (count == 1 || count == 2 || count == 4) {
+            // These are the only valid channel counts for the buffer.
+            success = Should(message, function () {
+              convolver.buffer = buffer;
+            }).notThrow() && success;
+          } else {
+            success = Should(message, function () {
+              convolver.buffer = buffer;
+            }).throw("NotSupportedError") && success;
+          }
+        }
+
+        if (success)
+          testPassed("Multiple channels for the convolver correctly handled.");
+        else
+          testFailed("Multiple channels for the convolver were not correctly handled.");
+
+        done();
+      });      
+
+      audit.defineTask("finish", function (done) {
+        finishJSTest();
+        done();
+      });
+
+      audit.runTasks();
+    </script>
+  </body>
+</html>

third_party/WebKit/Source/modules/webaudio/ConvolverNode.cpp

@@ -111,11 +111,16 @@ void ConvolverHandler::setBuffer(AudioBuffer* buffer, ExceptionState& exceptionS
     unsigned numberOfChannels = buffer->numberOfChannels();
     size_t bufferLength = buffer->length();
 
-    // The current implementation supports up to four channel impulse responses, which are interpreted as true-stereo (see Reverb class).
-    bool isBufferGood = numberOfChannels > 0 && numberOfChannels <= 4 && bufferLength;
-    ASSERT(isBufferGood);
-    if (!isBufferGood)
+    // The current implementation supports only 1-, 2-, or 4-channel impulse responses, with the
+    // 4-channel response being interpreted as true-stereo (see Reverb class).
+    bool isChannelCountGood = numberOfChannels == 1 || numberOfChannels == 2 || numberOfChannels == 4;
+
+    if (!isChannelCountGood) {
+        exceptionState.throwDOMException(
+            NotSupportedError,
+            "The buffer must have 1, 2, or 4 channels, not " + String::number(numberOfChannels));
         return;
+    }
 
     // Wrap the AudioBuffer by an AudioBus. It's an efficient pointer set and not a memcpy().
     // This memory is simply used in the Reverb constructor and no reference to it is kept for later use in that class.