Implement suspend() and resume() for OfflineAudioContext

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

Index: third_party/WebKit/Source/modules/webaudio/DeferredTaskHandler.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/DeferredTaskHandler.cpp b/third_party/WebKit/Source/modules/webaudio/DeferredTaskHandler.cpp
index cba5a99247ab2929a07aae6107dbb4a70cfee023..5ff4b2f204a06f5ebab4d50b16c1ede6e7f364a2 100644
--- a/third_party/WebKit/Source/modules/webaudio/DeferredTaskHandler.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/DeferredTaskHandler.cpp
@@ -28,6 +28,7 @@
 
 #include "modules/webaudio/AudioNode.h"
 #include "modules/webaudio/AudioNodeOutput.h"
+#include "modules/webaudio/OfflineAudioContext.h"
 #include "platform/ThreadSafeFunctional.h"
 #include "public/platform/Platform.h"
 #include "wtf/MainThread.h"
@@ -60,6 +61,17 @@ void DeferredTaskHandler::unlock()
     m_contextGraphMutex.unlock();
 }
 
+void DeferredTaskHandler::offlineLock()
+{
+    // It is safe to lock the graph from the audio thread for offline rendering,
+    // but let us have RELEASE_ASSERT here to make sure to explicitly crash
+    // rather than accidentally blocking the audio thread.

[Raymond Toy, 2015/10/22 18:49:47]

This comment kind of doesn't make sense.  You say it's safe to lock from the
audio thread, but there's a RELEASE_ASSERT.  This can't really both be true.  I
would fix the comment and remove the "safe to lock" stuff.

[hongchan, 2015/10/22 20:17:04]

Done.

+    RELEASE_ASSERT_WITH_MESSAGE(isAudioThread(),
+        "DeferredTaskHandler::offlineLock() should be called within the audio thread.");
+
+    m_contextGraphMutex.lock();
+}
+
 #if ENABLE(ASSERT)
 bool DeferredTaskHandler::isGraphOwner()
 {
@@ -226,12 +238,19 @@ void DeferredTaskHandler::contextWillBeDestroyed()
     // Some handlers might live because of their cross thread tasks.
 }
 
+
 DeferredTaskHandler::AutoLocker::AutoLocker(AbstractAudioContext* context)
     : m_handler(context->deferredTaskHandler())
 {
     m_handler.lock();
 }
 
+DeferredTaskHandler::OfflineGraphAutoLocker::OfflineGraphAutoLocker(OfflineAudioContext* context)
+    : m_handler(context->deferredTaskHandler())
+{
+    m_handler.offlineLock();
+}
+
 void DeferredTaskHandler::addRenderingOrphanHandler(PassRefPtr<AudioHandler> handler)
 {
     ASSERT(handler);