Support AudioContextOptions latencyHint as double.

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

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/webaudio/AudioContext.h"
 
 #include "core/dom/Document.h"
 #include "core/testing/DummyPageHolder.h"
 #include "platform/testing/TestingPlatformSupport.h"
 #include "public/platform/WebAudioDevice.h"
@@ skipping 32 matching lines @@
     switch (latencyHint.category()) {
       case WebAudioLatencyHint::kCategoryInteractive:
         bufferSize = audioHardwareBufferSize();
         break;
       case WebAudioLatencyHint::kCategoryBalanced:
         bufferSize = audioHardwareBufferSize() * 2;
         break;
       case WebAudioLatencyHint::kCategoryPlayback:
         bufferSize = audioHardwareBufferSize() * 4;
         break;
+      case WebAudioLatencyHint::kCategoryExact:
+        bufferSize = std::max(
+            static_cast<double>(audioHardwareBufferSize()),
+            std::min(latencyHint.seconds() * audioHardwareSampleRate(),
+                     static_cast<double>(audioHardwareBufferSize() * 4)));
+        break;
       default:
         NOTREACHED();
         break;
     }
 
     return new MockWebAudioDevice(audioHardwareSampleRate(), bufferSize);
   }
 
   double audioHardwareSampleRate() override { return 44100; }
   size_t audioHardwareBufferSize() override { return 128; }
@@ skipping 29 matching lines @@
       AudioContext::create(document(), balancedOptions, ASSERT_NO_EXCEPTION);
   EXPECT_GT(balancedContext->baseLatency(), interactiveContext->baseLatency());
 
   AudioContextOptions playbackOptions;
   playbackOptions.setLatencyHint(
       AudioContextLatencyCategoryOrDouble::fromAudioContextLatencyCategory(
           "playback"));
   AudioContext* playbackContext =
       AudioContext::create(document(), playbackOptions, ASSERT_NO_EXCEPTION);
   EXPECT_GT(playbackContext->baseLatency(), balancedContext->baseLatency());
+
+  AudioContextOptions exactTooSmallOptions;
+  exactTooSmallOptions.setLatencyHint(
+      AudioContextLatencyCategoryOrDouble::fromDouble(0.000001));
+  AudioContext* exactTooSmallContext = AudioContext::create(
+      document(), exactTooSmallOptions, ASSERT_NO_EXCEPTION);
+  EXPECT_EQ(exactTooSmallContext->baseLatency(),
+            interactiveContext->baseLatency());
+
+  const double exactLatencySec = 0.01;
+  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(1));
+  AudioContext* exactTooBigContext =
+      AudioContext::create(document(), exactTooBigOptions, ASSERT_NO_EXCEPTION);
+  EXPECT_EQ(exactTooBigContext->baseLatency(), playbackContext->baseLatency());
 }
 
 }  // namespace blink