Support AudioContextOptions latencyHint as double.

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

Index: third_party/WebKit/Source/modules/webaudio/AudioContextTest.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/AudioContextTest.cpp b/third_party/WebKit/Source/modules/webaudio/AudioContextTest.cpp
index a76bd7beb6c200d93fd7d62602ea9445a5f9a5b9..c77c42d90fbbe305b38752bb70831b6b54d12878 100644
--- a/third_party/WebKit/Source/modules/webaudio/AudioContextTest.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/AudioContextTest.cpp
@@ -40,15 +40,23 @@ class AudioContextTestPlatform : public TestingPlatformSupport {
                                     const WebString& deviceId,
                                     const WebSecurityOrigin&) override {
     double bufferSize = 0;
+    const double interactiveSize = audioHardwareBufferSize();
+    const double balancedSize = audioHardwareBufferSize() * 2;
+    const double playbackSize = audioHardwareBufferSize() * 4;
     switch (latencyHint.category()) {
       case WebAudioLatencyHint::kCategoryInteractive:
-        bufferSize = audioHardwareBufferSize();
+        bufferSize = interactiveSize;
         break;
       case WebAudioLatencyHint::kCategoryBalanced:
-        bufferSize = audioHardwareBufferSize() * 2;
+        bufferSize = balancedSize;
         break;
       case WebAudioLatencyHint::kCategoryPlayback:
-        bufferSize = audioHardwareBufferSize() * 4;
+        bufferSize = playbackSize;
+        break;
+      case WebAudioLatencyHint::kCategoryExact:
+        bufferSize = clampTo(latencyHint.seconds() * audioHardwareSampleRate(),
+                             static_cast<double>(audioHardwareBufferSize()),
+                             static_cast<double>(playbackSize));
         break;
       default:
         NOTREACHED();
@@ -99,6 +107,32 @@ TEST_F(AudioContextTest, AudioContextOptions_WebAudioLatencyHint) {
   AudioContext* playbackContext =
       AudioContext::create(document(), playbackOptions, ASSERT_NO_EXCEPTION);
   EXPECT_GT(playbackContext->baseLatency(), balancedContext->baseLatency());
+
+  AudioContextOptions exactTooSmallOptions;
+  exactTooSmallOptions.setLatencyHint(
+      AudioContextLatencyCategoryOrDouble::fromDouble(
+          interactiveContext->baseLatency() / 4));
+  AudioContext* exactTooSmallContext = AudioContext::create(
+      document(), exactTooSmallOptions, ASSERT_NO_EXCEPTION);
+  EXPECT_EQ(exactTooSmallContext->baseLatency(),
+            interactiveContext->baseLatency());
+
+  const double exactLatencySec =
+      (interactiveContext->baseLatency() + playbackContext->baseLatency()) / 4;
+  AudioContextOptions exactOkOptions;
+  exactOkOptions.setLatencyHint(
+      AudioContextLatencyCategoryOrDouble::fromDouble(exactLatencySec));
+  AudioContext* exactOkContext =
+      AudioContext::create(document(), exactOkOptions, ASSERT_NO_EXCEPTION);
+  EXPECT_EQ(exactOkContext->baseLatency(), exactLatencySec * 2);
+
+  AudioContextOptions exactTooBigOptions;
+  exactTooBigOptions.setLatencyHint(
+      AudioContextLatencyCategoryOrDouble::fromDouble(
+          playbackContext->baseLatency() * 2));
+  AudioContext* exactTooBigContext =
+      AudioContext::create(document(), exactTooBigOptions, ASSERT_NO_EXCEPTION);
+  EXPECT_EQ(exactTooBigContext->baseLatency(), playbackContext->baseLatency());
 }
 
 }  // namespace blink