Added Dartium changes onto 45.0.2454.104

Source/wtf/ArrayBuffer.h

Index: Source/wtf/ArrayBuffer.h
diff --git a/Source/wtf/ArrayBuffer.h b/Source/wtf/ArrayBuffer.h
index d83dd2e7b062e91cdb907ccfa14a9849bc79ea71..675ee57f47d47b6dcf400e3b3df16db8b5b28f7d 100644
--- a/Source/wtf/ArrayBuffer.h
+++ b/Source/wtf/ArrayBuffer.h
@@ -44,6 +44,16 @@ public:
     static inline PassRefPtr<ArrayBuffer> create(const void* source, unsigned byteLength);
     static inline PassRefPtr<ArrayBuffer> create(ArrayBufferContents&);
 
+    // Create an ArrayBuffer for an existing piece of memory with no copying.
+    // The ArrayBuffer does not take ownership of the passed-in memory and care
+    // must be taken to not deallocate the data before the ArrayBuffer has been
+    // deallocated.
+    //
+    // FIXME: This should be removed when pointers into the JS/Dart heap can
+    // can be passed directly.
+    static inline PassRefPtr<ArrayBuffer> createNoCopy(void* source, unsigned byteLength);
+
+    // Only for use by Uint8ClampedArray::createUninitialized and SharedBuffer::getAsArrayBuffer.
     static inline PassRefPtr<ArrayBuffer> createOrNull(unsigned numElements, unsigned elementByteSize);
 
     // Only for use by XMLHttpRequest::responseArrayBuffer and Internals::serializeObject
@@ -120,6 +130,13 @@ PassRefPtr<ArrayBuffer> ArrayBuffer::create(const void* source, unsigned byteLen
     return buffer.release();
 }
 
+PassRefPtr<ArrayBuffer> ArrayBuffer::createNoCopy(void* source, unsigned byteLength)
+{
+    // FIXME: What do we pass in for a DeallocationObserver?
+    ArrayBufferContents contents(source, byteLength, ArrayBufferContents::SharingType::NotShared);
+    return adoptRef(new ArrayBuffer(contents));
+}
+
 PassRefPtr<ArrayBuffer> ArrayBuffer::create(ArrayBufferContents& contents)
 {
     RELEASE_ASSERT(contents.data());
@@ -175,7 +192,10 @@ PassRefPtr<ArrayBuffer> ArrayBuffer::createShared(unsigned numElements, unsigned
 ArrayBuffer::ArrayBuffer(ArrayBufferContents& contents)
     : m_firstView(0), m_isNeutered(false)
 {
-    contents.transfer(m_contents);
+    if (contents.isShared())
+        contents.shareWith(m_contents);
+    else
+        contents.transfer(m_contents);
 }
 
 void* ArrayBuffer::data()