MSE: Complete letting SourceBuffer begin to do initialization segment received algorithm

This change is the third in a three-sided set of changes, and lets
WebSourceBufferClient be the sole trigger for Blink adding a
SourceBuffer into SourceBuffer.activeSourceBuffers.

R=acolwell@chromium.org,philipj@opera.com,tkent@chromium.org
TEST=No mediasource layout test regression
BUG=249428, 397243

Review URL: https://codereview.chromium.org/562503002

git-svn-id: svn://svn.chromium.org/blink/trunk@181949 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/TestExpectations

@@ -466,13 +466,6 @@ crbug.com/340206 [ Win ] http/tests/security/cross-origin-css.html [ Pass Timeou
 crbug.com/283723 [ Win ] http/tests/local/fileapi/file-last-modified-after-delete.html [ Failure Pass Timeout ]
 crbug.com/371716 [ Win ] http/tests/local/formdata/send-form-data.html [ Pass Timeout ]
 
-# Temporary failures while landing three-sided changes
-crbug.com/249428 http/tests/media/media-source/mediasource-addsourcebuffer.html [ Failure ]
-crbug.com/249428 http/tests/media/media-source/mediasource-append-buffer.html [ Failure ]
-crbug.com/249428 http/tests/media/media-source/mediasource-append-legacystream.html [ Failure ]
-crbug.com/249428 http/tests/media/media-source/mediasource-buffered.html [ Failure ]
-crbug.com/249428 http/tests/media/media-source/mediasource-sourcebufferlist.html [ Failure ]
-
 # 309184 and 303419 track Android-specific failures
 crbug.com/309184 crbug.com/303419 crbug.com/284782 http/tests/media/media-source/mediasource-duration.html [ Failure Pass ]
 

third_party/WebKit/Source/modules/mediasource/MediaSource.cpp

@@ -155,8 +155,6 @@ SourceBuffer* MediaSource::addSourceBuffer(const String& type, ExceptionState& e
     SourceBuffer* buffer = SourceBuffer::create(webSourceBuffer.release(), this, m_asyncEventQueue.get());
     // 6. Add the new object to sourceBuffers and fire a addsourcebuffer on that object.
     m_sourceBuffers->add(buffer);
-    // FIXME: Remove the following once Chromium calls WebSourceBufferClient::InitSegmentReceived()
-    setSourceBufferActive(buffer);
 
     // 7. Return the new object to the caller.
     return buffer;
@@ -484,8 +482,7 @@ bool MediaSource::isOpen() const
 
 void MediaSource::setSourceBufferActive(SourceBuffer* sourceBuffer)
 {
-    if (m_activeSourceBuffers->contains(sourceBuffer))
-        return;
+    ASSERT(!m_activeSourceBuffers->contains(sourceBuffer));
 
     // https://dvcs.w3.org/hg/html-media/raw-file/tip/media-source/media-source.html#widl-MediaSource-activeSourceBuffers
     // SourceBuffer objects in SourceBuffer.activeSourceBuffers must appear in

third_party/WebKit/public/platform/WebSourceBuffer.h

@@ -48,10 +48,7 @@ public:
 
     // This will only be called once and only with a non-null pointer to a
     // client whose ownership is not transferred to this WebSourceBuffer.
-    virtual void setClient(WebSourceBufferClient*)
-    {
-        // FIXME: Remove default implementation once Chromium impl lands.
-    }
+    virtual void setClient(WebSourceBufferClient*) = 0;
 
     virtual bool setMode(AppendMode) = 0;
     virtual WebTimeRanges buffered() = 0;